Agreement - WebMD Inc. and McKesson HBOC Inc.


                                    AGREEMENT

         This Agreement (this "AGREEMENT") is entered into as of this 1st day of
September, 1999, by and among WebMD, Inc., a Georgia corporation ("WEBMD"),
McKesson HBOC, Inc., a Delaware corporation ("MCKESSON"), HBO & Company, a
Delaware corporation ("HBOC") and a wholly owned subsidiary of McKesson and
successor by merger to HBO & Company of Georgia (McKesson and HBOC being
referred to collectively herein as "MCKHBOC"), and, for purposes of Section 2,
Section 3.2, Section 3.4, Section 3.6 and Section 4.1 of this Agreement only,
Healtheon Corporation, a Delaware corporation ("HEALTHEON"), and Healtheon/WebMD
Corporation, a Delaware corporation ("HEALTHEON/WEBMD").

                                    RECITALS

         A. As of December 30, 1997, Endeavor Technologies, Inc., a Georgia
corporation and predecessor to WebMD, and National Health Enhancement Systems,
Inc., formerly wholly owned subsidiary of McKesson which has since been merged
into HBOC ("NHES"), entered into a License Agreement (the "ENDEAVOR/NHES LICENSE
AGREEMENT"). On October 23, 1998, WebMD and HBOC entered into a Strategic
Distribution Alliance Agreement (the "STRATEGIC DISTRIBUTION ALLIANCE
AGREEMENT"). On November 3, 1998, the Strategic Distribution Alliance Agreement
was amended by an addendum (the "ADDENDUM"). The Strategic Distribution Alliance
Agreement was further amended by a letter effective December 31, 1998 (the
"DECEMBER LETTER AGREEMENT"). On January 20, 1999, McKesson and WebMD entered
into a certain letter agreement (the "JANUARY LETTER AGREEMENT"). The
Endeavor/NHES License Agreement, the Strategic Distribution Alliance Agreement,
the Addendum, the December Letter Agreement and the January Letter Agreement are
referred to herein as the "STRATEGIC AGREEMENTS."

         B. As of March 31, 1999, Access Health, Inc., which has since been
merged into HBOC ("ACCESS"), and WebMD entered into the following agreements
relating to certain clinical reference products as set forth on Attachment II
and Exhibit A, respectively of the agreements described in clauses (1) and (2)
herein (the "CLINICAL REFERENCE PRODUCTS") and related domain names and
trademarks: (1) a License Agreement whereby the Clinical Reference Products were
licensed by Access to WebMD; (2) an Option Agreement whereby Access granted
WebMD an option to purchase certain related domain names and trademark rights;
(3) an Option Agreement whereby Access granted WebMD an option to purchase the
Clinical Reference Products; and (4) an agreement creating a grant-back license
from WebMD to Access contingent upon WebMD's exercise of the option to purchase
the Clinical Reference Products. The foregoing agreements, as they may have been
supplemented or amended, are referred to herein as the "PRODUCT AGREEMENTS."

         C. Pursuant to an Investment Agreement dated August 24, 1998, amended
by an amendment dated October 23, 1998 and an amendment dated January 28, 1999
(together, the "SERIES A INVESTMENT AGREEMENT"), HBOC purchased 667,000 shares
of Series A Preferred Stock of WebMD, received a warrant (the "SERIES A
WARRANT") for 300,000 shares of Series A Preferred Stock of WebMD and received a
performance warrant (the "PERFORMANCE WARRANT") for up to 200,000 shares of
Series A Preferred Stock of WebMD. In addition, pursuant to the Series A
Investment Agreement, HBOC was granted the right to receive up to an additional
200,000 shares of Series A Preferred Stock of WebMD in the event that WebMD did
not complete an Initial Public Offering (as defined in the

>PAGE>   2

Series A Investment Agreement) prior to certain specified dates. As of the date
hereof, HBOC has received 150,000 of these shares and will be entitled to
receive an additional 50,000 shares if WebMD has not completed an Initial Public
Offering prior to November 22, 1999 (the "ADDITIONAL DELAY SHARES").

         D. On January 28, 1999, HBOC purchased 650,000 shares of Series B
Preferred Stock of WebMD pursuant to an Investment Agreement of that date (the
"SERIES B INVESTMENT AGREEMENT"). The Series A Investment Agreement, Series B
Investment Agreement, the Series A Warrant and the Performance Warrant are
referred to herein as the "WEBMD INVESTMENT DOCUMENTS."

         E. On April 9, 1999, WebMD declared a stock dividend of .03846 shares
of its Series F preferred stock ("SERIES F PREFERRED STOCK") with respect to
each outstanding share of capital stock of WebMD and made a proportionate
adjustment to the Series A Warrant in lieu of providing HBOC with advance notice
of such dividend (as required by the Series A Warrant). No adjustment was made
to the Performance Warrant as no adjustment was provided for in the terms of the
Performance Warrant. On April 30, 1999, HBOC exercised the Series A Warrant and
received 300,000 shares of Series A Preferred Stock and 11,538 shares of Series
F Preferred Stock.

         F. In a series of transactions commencing May 12, 1999, WebMD sold to
Microsoft Corporation and other strategic purchasers an aggregate of 461,510
shares of its Series E Preferred Stock at a per share price of $541.70, 184,604
shares of its Series D Common Stock for a per share price of $54.17 and a
warrant (to Microsoft) to purchase 7,614,916 shares of Series D Common Stock.
WebMD's Series E Preferred Stock is convertible on a one-for-ten basis into
WebMD's Common Stock. As a result of these sales and pursuant to the rights of
HBOC contained in the WebMD Investment Documents, HBOC has the right (the "HBOC
PURCHASE RIGHTS") to purchase 38,773 shares of Series E Preferred Stock of
WebMD, 16,745 shares of Series D Common Stock of WebMD and a warrant exercisable
for 636,980 shares of Series D Common Stock, which right shall become
exercisable for a ten day period upon notice by WebMD to HBOC, which notice
WebMD has not yet given.

         G. On March 1, 1999, WebMD issued 200,000 shares of its Series D
Preferred Stock to Cable News Network LP, LLP ("CNN") in exchange for
promotional considerations described in the Agreement for Branding and On-Air
Promotion dated as of January 28, 1999 between CNN and WebMD. On March 30, 1999,
WebMD issued to E.I. du Pont de Nemours and Company ("DUPONT") a warrant to
purchase 4,000,000 shares of WebMD's Series D Common Stock in exchange for a
Collaboration Agreement between WebMD and DuPont dated March 30, 1999. HBOC has
contended that it has a right to purchase a proportional amount of the Series D
Preferred Stock issued to CNN and the warrant to purchase Series D Common Stock
issued to DuPont (the "DISPUTED HBOC PURCHASE RIGHTS"). WebMD believes that HBOC
has no such rights.

         H. The Performance Warrant provides that the right to purchase 66,666
shares of Series A Preferred Stock of WebMD potentially issuable pursuant
thereto shall vest and become exercisable on March 31, 1999 if the joint
marketing efforts of HBOC and WebMD generated for WebMD gross revenues of
$1,000,000 for the twelve months ended March 31, 1999. By letter from its
counsel dated April 30, 1999, HBOC has contended that the Performance Warrant
became vested and exercisable with respect to such shares because it believes
that such criteria were met. WebMD does not believe that such criteria were met.


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         I. On May 20, 1999, WebMD entered into an Agreement and Plan of
Reorganization (as the same may be amended from time to time, the
"HEALTHEON-WEBMD REORGANIZATION AGREEMENT") with Healtheon which provides for
the combination of the businesses of WebMD and Healtheon. The Healtheon-WebMD
Reorganization Agreement provides for such transaction to be effected through
one of two structures: a subsidiary of Healtheon/WebMD may be merged with and
into Healtheon and another subsidiary of Healtheon/WebMD merged into WebMD
("REORGANIZATION STRUCTURE ONE") or a subsidiary of Healtheon may be merged with
and into WebMD ("REORGANIZATION STRUCTURE TWO"). On June 17, 1999,
Healtheon/WebMD filed a Registration Statement on Form S-4 (File No. 333-80863)
(as the same may be amended from time to time, the "HEALTHEON/WEBMD REGISTRATION
STATEMENT") with the Securities and Exchange Commission (the "COMMISSION")
describing Reorganization Structure One as well as the acquisition by
Healtheon/WebMD of the business of MEDE AMERICA Corporation, a Delaware
corporation; it is anticipated that if the transaction is to be effected through
Reorganization Structure Two, the Healtheon/WebMD Registration Statement will be
amended to reflect that, among other things, Healtheon will be the issuer of the
securities registered pursuant thereto. The transactions described in the
Healtheon-WebMD Reorganization Agreement and in the Healtheon/WebMD Registration
Statement, as the same may be amended from time to time, are referred to herein
as the "REORGANIZATION."

         J. In anticipation of the consummation of the Reorganization, the
parties to this Agreement desire to modify the Strategic Agreements, the Product
Agreements and the WebMD Investment Documents and to provide for McKesson's and
HBOC's concurrence with and support of the transactions contemplated by the
Reorganization.

         NOW, THEREFORE, it is agreed as follows:

         1. TERMINATION OF CERTAIN AGREEMENTS; NEW ARRANGEMENTS.

            1.1 TERMINATION OF STRATEGIC AGREEMENTS; NEW STRATEGIC ARRANGEMENTS.
The parties to this Agreement include all of the parties to each of the
Strategic Agreements. As of the date of this Agreement, each of the Strategic
Agreements shall be, without the need for any further action on the part of any
party, terminated and shall be of no further force and effect. No party to any
Strategic Agreement shall have any further rights or obligations with respect to
such Strategic Agreement or be required from and after the termination thereof
pursuant to this Section 1.1, to take, or refrain from taking, any action
whatsoever pursuant to such Strategic Agreement. In lieu of the Strategic
Agreements, WebMD and McKHBOC hereby agree to the provisions set forth on
EXHIBIT 1.1 which shall become effective as of the date hereof.

            Except as set forth in EXHIBIT 1.1, as of the date of this
Agreement, each party hereby fully releases the other party from any and all
obligations, and agrees not to seek any costs, damages or other compensation
from the other party under any legal theory including, without limitation,
breach of contract, breach of warranty, restitution or quantum meruit, arising
from the Strategic Agreements or termination thereof.

            1.2 TERMINATION OF PRODUCT AGREEMENTS; NEW PRODUCT ARRANGEMENTS. The
parties to this Agreement include all of the parties to each of the Product
Agreements. As of the date of this Agreement, each of the Product Agreements
shall be, without the need for any further action on the part of any party,
terminated and shall be of no further force and effect. No party to any Product
Agreement shall have any further rights or obligations with respect to such
Product Agreement or be required from and after the termination thereof pursuant
to this Section

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>PAGE>   4

1.2, to take, or refrain from taking, any action whatsoever pursuant to such
Product Agreement. In lieu of the Product Agreements, WebMD and McKHBOC hereby
agree to the provisions set forth on EXHIBIT 1.2, which shall become effective
as of the date this Agreement is entered into.

            In accordance with the foregoing, immediately upon execution of this
Agreement, all right, title and interest that was granted to WebMD under the
Product Agreements shall revert to McKHBOC without the need for any further
action on the part of any party. WebMD hereby represents and warrants that it
has made no grants or transfers to any third party of or under any right, title
or interest pursuant to the Product Agreements and hereby quitclaims all such
right, title and interest to McKHBOC.

            Except as set forth in EXHIBIT 1.2, each party hereby fully releases
the other party from any and all obligations, and agrees not to seek any costs,
damages or other compensation from the other party under any legal theory
including, without limitation, breach of contract, breach of warranty,
restitution or quantum meruit, arising from the Product Agreements or
termination thereof.

         2. ISSUANCE AND DELIVERY OF WARRANTS.

         2.1. ISSUANCE OF WARRANTS. In exchange for the relinquishment of the
HBOC Purchase Rights and the Disputed HBOC Purchase Rights and in consideration
for the additional covenants and agreements of McKHBOC contained herein, WebMD
agrees to issue to HBOC upon execution of this Agreement: (i) a warrant to
purchase 1,837,417 shares of the Common Stock Series F, no par value per share,
of WebMD (the "SERIES F COMMON STOCK") (which (A) shall be exercisable at a per
share price of $91.34, or (B) if exercised after the closing of the
Reorganization (the "HEALTHEON-WEBMD CLOSING"), and subject to adjustment as
described below, shall be exercisable for: (x) 3,300,000 shares of common stock,
par value $0.0001 per share, of Healtheon/WebMD (the "HEALTHEON/WEBMD COMMON
STOCK"), at a per share price of $50.86 in the event the Reorganization is
effected through Reorganization Structure One, or (y) 3,300,000 shares of common
stock, par value $0.0001 per share, of Healtheon (the "HEALTHEON COMMON STOCK"),
at a per share price of $50.86 in the event the Reorganization is effected
through Reorganization Structure Two, (ii) a warrant to purchase 2,783,965
shares of Series F Common Stock (which (A) shall be exercisable at a price per
share equal to $54.17, or (B) if exercised after the Healtheon-WebMD Closing,
and subject to adjustment as described below, shall be exercisable for: (x)
5,000,000 shares of Healtheon/WebMD Common Stock at a price per share equal to
$30.16 in the event the Reorganization is effected through Reorganization
Structure One, or (y) 5,000,000 shares of Healtheon Common Stock at a price per
share equal to $30.16 the event the Reorganization is effected through
Reorganization Structure Two) and (iii) a warrant to purchase 66,667 shares of
Series F Common Stock (which (A) shall be exercisable at a price per share equal
to $20.00, or (B) if exercised after the Healtheon-WebMD Closing, and subject to
adjustment as described below, shall be exercisable for: (x) 119,734 shares of
Healtheon/WebMD Common Stock at a price per share equal to $11.14 in the event
the Reorganization is effected through Reorganization Structure One, or (y)
119,734 shares of Healtheon Common Stock at a price per share equal to $11.14 in
the event the Reorganization is effected through Reorganization Structure
Two)(collectively, the "NEW WARRANTS"), each of which shall be in the form of
EXHIBIT 2.1 hereto. The number of shares of Healtheon/WebMD Common Stock or
Healtheon Common Stock to be issued upon exercise of the New Warrants in the
event the New Warrants are exercised after the Healtheon-WebMD Closing and the
exercise price thereof as set forth in this Section 2.1 gives effect, in each
case, to the reduction in the exchange ratio resulting from the transactions
described in this Agreement as set forth in Section 3.6. To the extent the
exchange ratio is changed by agreement among the parties to the Healtheon-WebMD
Reorganization Agreement after the date hereof, the number of shares of
Healtheon/WebMD Common Stock or

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>PAGE>   5

Healtheon Common Stock for which the New Warrants may be exercised and the
exercise price thereof shall be adjusted to reflect the revised exchange ratio,
except that any further reduction in the exchange ratio as a result of or
arising out of this Agreement shall not result in any modification of the number
of shares of Healtheon/WebMD Common Stock or Healtheon Common Stock to be issued
upon the exercise of the New Warrants or any adjustment to the exercise price.
WebMD shall reserve and keep available for issuance at all times, free from any
liens or encumbrances, preemptive rights, rights of first refusal or redemption
rights, such number of its authorized but unissued shares of Series F Common
Stock (or Common Stock without Series designation if the New Warrants become
exercisable for such stock pursuant to Section 2.4 below) as is sufficient to
permit exercise in full of each of the New Warrants in accordance with the terms
thereof. All shares of Series F Common Stock that are so issuable shall, when
issued upon exercise and payment therefor, be fully and validly issued and fully
paid and non-assessable. Upon the Healtheon-WebMD Closing, Healtheon/WebMD (in
the event the Reorganization is effected through Reorganization Structure One)
or Healtheon (in the event the Reorganization is effected through Reorganization
Structure Two) shall assume all obligations of WebMD with respect to the New
Warrants, and the New Warrants shall be exercisable for shares of
Healtheon/WebMD Common Stock or Healtheon Common Stock, as applicable, as
provided in this Section 2.1.

         2.2. DELIVERY OF WARRANTS. Subject to Section 3.2 below, WebMD shall
deliver the New Warrants to HBOC concurrently with the execution of this
Agreement.

         2.3. REGISTRATION RIGHTS AGREEMENT. Upon the issuance of the New
Warrants, WebMD shall enter into a Registration Rights Agreement with HBOC
substantially in the form of EXHIBIT 2.3 hereto.

         2.4. CREATION OF SERIES F COMMON STOCK. Prior to the execution of this
Agreement, the Board of Directors of WebMD approved the Articles of Amendment to
the Amended and Restated Articles of Incorporation of WebMD in the form attached
hereto as EXHIBIT 2.4 ("Articles of Amendment") and called a meeting of the
holders of WebMD's Common Stock without Series designation and Series A
Preferred Stock for the purpose of adopting such Articles of Amendment. WebMD
shall use its best commercial efforts to hold such meeting and cause such
Articles of Amendment to be adopted and when adopted shall file such Articles of
Amendment with the Secretary of State of the State of Georgia. HBOC agrees to
vote its shares of Series A Preferred Stock in favor of the adoption of such
Articles of Amendment and to waive notice of the shareholders meeting if
requested to do so by WebMD. In the event such Articles of Amendment are not so
filed prior to September 20, 1999, then anything in this Agreement or the New
Warrants to the contrary notwithstanding, the New Warrants shall be exercisable
for Common Stock of WebMD without Series designation if exercised prior to the
Healtheon-WebMD Closing and all references to "Common Stock" in the New Warrant
shall mean Common Stock of WebMD without Series designation.

         3.   HEALTHEON/WEBMD REORGANIZATION.

         3.1. VOTING AGREEMENT. HBOC agrees to execute, simultaneously with the
execution of this Agreement, a Voting Agreement substantially in the form of
EXHIBIT 3.1 hereof.

         3.2. HART-SCOTT-RODINO. In the event that the acquisition of the New
Warrants or the shares issuable upon exercise of the New Warrants by HBOC
pursuant to this Agreement would require any filing by McKHBOC under the
Hart-Scott-Rodino Antitrust Improvements Act of 1976 (the "HSR ACT"), then
before such New Warrants or shares shall be issued to HBOC, McKesson shall
prepare and

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file with the United States Federal Trade Commission and the Antitrust Division
of the United States Department of Justice Notification and Report Forms as an
"acquiring person" as required by the HSR Act. Each of WebMD, Healtheon and
Healtheon/WebMD shall cooperate with McKesson in making any such filing, and
shall make any filing required of any of them in connection therewith, promptly
and shall furnish McKesson such information and commercially reasonable
assistance as necessary for any such filing.

         3.3. TERMINATION OF CERTAIN AGREEMENTS; SPECIAL COVENANTS. (a)
Effective on the date hereof, (i) HBOC agrees to take all such action requested
by WebMD so that each of the Restated Stockholders Agreement dated October 18,
1996, as amended (the "WEBMD RESTATED STOCKHOLDERS AGREEMENT"), and the
Shareholders Agreement dated August 24, 1998, as amended (the "WEBMD
SHAREHOLDERS AGREEMENT"), shall be terminated and of no further force and effect
without the need for any further action on the part of any party thereto and
(ii) subject to Section 3.3(b) below, all rights and obligations of the parties
pursuant to each of the WebMD Investment Documents (including, without
limitation, the Performance Warrant and the HBOC Purchase Rights) shall be
terminated and of no further force and effect. WebMD and McKHBOC hereby waive
any claim that such party may have with respect to any alleged breach of any of
the Strategic Agreements, the Product Agreements, the WebMD Restated
Stockholders Agreement, the WebMD Shareholders Agreement and the WebMD
Investment Documents arising prior to the date hereof.

         (b) WebMD acknowledges that McKHBOC has agreed to the termination of
the WebMD Restated Stockholders Agreement, the WebMD Shareholders Agreement and
the WebMD Investment Documents prior to the Healtheon-WebMD Closing based on its
understanding that, as of the date hereof, (i) WebMD has not granted any
currently outstanding preemptive rights to purchase its capital stock to any
person, and (ii) WebMD has not granted to any person registration rights with
respect to its capital stock which are more favorable than the registration
rights currently held by McKHBOC. If at any time after the date hereof, WebMD
grants preemptive rights to acquire any of its capital stock, and if the
Healtheon-WebMD Reorganization Agreement is terminated, WebMD shall grant to
McKHBOC preemptive rights on terms equivalent to those granted to such other
person(s). WebMD further covenants that if the Healtheon-WebMD Reorganization
Agreement is terminated, then McKHBOC shall continue to have the information and
access rights set forth in Sections 7.1.1, 7.1.2 and 7.1.4(a) and (c) of the
Series A Investment Agreement as long as it owns at least 1% of the capital
stock of WebMD on a fully diluted basis and McKHBOC agrees that it shall
continue to be bound by the confidentiality obligations in Section 7.3 of the
Series A Investment Agreement. WebMD further covenants that if the
Healtheon-WebMD Reorganization Agreement is terminated, and if at any time after
the date hereof WebMD grants any registration rights to any person with respect
to its capital stock, then WebMD shall promptly (and in any event within five
days after being requested by McKHBOC) provide McKHBOC with copies of all
agreements pertaining to the registration of shares of WebMD's capital stock
under the Securities Act of 1933, as amended, and applicable state securities
laws, and permit McKHBOC to elect in writing within 30 days after WebMD has
provided such copies to McKHBOC to have the WebMD capital stock owned by it
treated as registrable securities under or otherwise covered by the provisions
of any one of such agreements as McKHBOC shall elect in lieu of the Registration
Rights Agreement, it being understood that if McKHBOC does not make such
election, it shall retain all of its rights pursuant to the Registration Rights
Agreement. Upon any such election WebMD shall enter into a new registration
rights agreement with McKHBOC and the Registration Rights Agreement shall
thereafter be of no further force and effect.

         3.4. VOTING; FURTHER ACTIONS. Pursuant and subject to the terms of the
Voting Agreement, HBOC agrees to vote all of its shares of capital stock of
WebMD entitled to vote "for" the 

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Reorganization and all transactions contemplated thereby upon which such shares
may be entitled to vote. McKHBOC agrees to take any further action reasonably
requested by WebMD to facilitate the Healtheon-WebMD Closing. Each of WebMD,
Healtheon and Healtheon/WebMD shall use its commercial best efforts to obtain
and assist HBOC in obtaining promptly all necessary waivers, consents and
approvals from any governmental authority or any other person for any exercise
by HBOC of its rights under this Agreement, or the New Warrants, and to take
such other actions as may reasonably be requested by HBOC to effect the purposes
of this Agreement, or the New Warrants. The period of time provided for any
closing of the transactions pursuant to such rights may, at the option of HBOC,
be extended as necessary in order to obtain any such waivers, consents and
approvals.

         3.5. ADDITIONAL DELAY SHARES. WebMD hereby agrees that, notwithstanding
any other provision of this Agreement to the contrary, HBOC shall have the right
to receive the Additional Delay Shares if WebMD has not completed an Initial
Public Offering prior to November 22, 1999.

         3.6. ADJUSTMENT TO EXCHANGE RATIO. The transactions contemplated by
this Agreement will result in a change in the ratio at which shares of WebMD
common stock will be exchanged for shares of Healtheon/WebMD Common Stock (in
the event the Reorganization is effected through Reorganization Structure One)
or Healtheon Common Stock (in the event the Reorganization is effected through
Reorganization Structure Two) such that, upon consummation of the Reorganization
and subject to any other changes in the Exchange Ratio agreed to among the
parties to the Healtheon-WebMD Reorganization Agreement after the date hereof,
each share of WebMD common stock and each share of WebMD preferred stock
(following its conversion to common stock) will be exchanged for (x) 1.796
shares of Healtheon/WebMD Common Stock, in the event the Reorganization is
effected through Reorganization Structure One, or (y) 1.796 shares of Healtheon
Common Stock, in the event the Reorganization is effected through Reorganization
Structure Two. Nothing in this Agreement shall preclude the amendment of the
Healtheon-WebMD Reorganization Agreement or require the consent or approval of
McKHBOC to any such amendment, including any amendment to the Exchange Ratio,
provided, however, that without the written consent of McKHBOC no amendment to
the Healtheon-WebMD Reorganization Agreement shall amend, modify or change the
shares of capital stock obtainable upon the exercise of the warrants to be
delivered hereunder in a manner that is adverse to the holder of such warrants
unless such amendment, modification or change is uniformly applicable to all of
the holders of such class and series of capital stock.

         4.   REPRESENTATIONS AND WARRANTIES.

         4.1. REPRESENTATIONS AND WARRANTIES OF WEBMD AND HEALTHEON. WebMD
hereby represents and warrants to McKHBOC with respect to itself and
Healtheon/WebMD, and Healtheon hereby separately represents and warrants to
McKHBOC with respect to itself and Healtheon/WebMD as follows:

              4.1.1. Organization and Standing. Each of WebMD, Healtheon and
Healtheon/WebMD is a corporation duly organized, validly existing and in good
standing under the laws of the jurisdiction of its incorporation and has all
necessary power and authority: (i) to conduct its business in the manner in
which its business is currently being conducted; (ii) to own and use its assets
in the manner in which its assets are currently owned and used; and (iii) to
perform its obligations under this Agreement and/or the Healtheon-WebMD
Reorganization Agreement. Each of WebMD, Healtheon and Healtheon/WebMD is
qualified to do business as a foreign corporation, and is in good standing,
under the laws of all jurisdictions where the nature of its business requires
such qualification and where the failure to so qualify would result in any
change, event, violation, inaccuracy, 


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circumstance or effect that is materially adverse to the business, assets
(including intangible assets), financial condition or results of operations of
WebMD, Healtheon or Healtheon/WebMD, as applicable, taken as a whole with its
respective subsidiaries.

              4.l.2. Authorization; Enforceability. All action on the part of
WebMD, Healtheon and Healtheon/WebMD necessary for the authorization, execution,
delivery and performance of all their respective obligations under this
Agreement or any document contemplated hereby has been taken. This Agreement,
when executed and delivered by each of WebMD, Healtheon and Healtheon/WebMD,
will constitute the valid and binding obligation of such party, and will be
enforceable against it in accordance with its terms, except as enforceability
may be limited by bankruptcy, insolvency or other laws affecting the enforcement
of creditors' rights generally, and except that the availability of the remedy
of specific performance or other equitable relief is subject to the discretion
of the court before which any proceeding therefor may be brought.

              4.1.3. Capitalization. As of the date of this Agreement, (i) the
capitalization of WebMD is as set forth on EXHIBIT 4.1(A) hereto. The
representations and warranties given by Healtheon to WebMD regarding Healtheon's
capitalization set forth in Section 3.2 of the Healtheon-WebMD Reorganization
Agreement were true and correct as of the date thereof in all material respects.

              4.1.4 Compliance with Other Instruments. The execution, delivery
and performance of and compliance with this Agreement, the Registration Rights
Agreement and the New Warrants and the issuance of the shares of Series F Common
Stock, Healtheon Common Stock or Healtheon/WebMD Common Stock upon the exercise
thereof will not result in any violation or be in conflict with or constitute a
default (with or without notice or lapse of time or both) under, or give rise to
a right of termination, cancellation or acceleration or the loss of any material
benefit under: (i) any of the terms or provisions of the Certificate of
Incorporation or Bylaws of WebMD, Healtheon or Healtheon/WebMD (or any
comparable organizational documents of such companies' subsidiaries), or (ii)
any mortgage, indenture, license, lease, contract, agreement or instrument to
which any of WebMD, Healtheon, Healtheon/WebMD, or any of their respective
subsidiaries is a party, or (iii) any judgment, order, decree, statue, law,
ordinance, rule or regulation applicable to WebMD, Healtheon, Healtheon/WebMD,
or any of their respective subsidiaries, properties or assets, or (iv) result in
the creation of any mortgage, pledge, lien, encumbrance or charge upon any of
the properties or assets of WebMD, Healtheon, Healtheon/WebMD, or any of their
respective subsidiaries pursuant to any such term or provision.

              4.1.5. Offering. Subject to the accuracy of the representations of
McKHBOC set forth in Section 4.2 below, the issuance of the New Warrants and the
securities issuable upon exercise of the New Warrants pursuant to this Agreement
constitute transactions exempt from the registration requirements of Section 5
of the Securities Act of 1933, as amended (the "SECURITIES ACT").

              4.1.6. Validity of Stock. The shares of Series F Common Stock,
Healtheon Common Stock or Healtheon/WebMD Common Stock, as applicable, issuable
upon exercise of the New Warrants, when issued, sold and delivered in compliance
with the provisions of this Agreement and the New Warrants, will be duly
authorized, validly issued, fully paid and nonassessable, will be free of any
liens or encumbrances, and will not be subject to any preemptive rights, rights
of first refusal or redemption rights.

              4.1.7. No Other Agreements. Except as evidenced in this Agreement,
the Strategic Agreements, the WebMD Investment Documents, the Product
Agreements, the WebMD Restated 

                                       8

>PAGE>   9

Stockholders Agreement, the WebMD Shareholders Agreement, WebMD's articles of
incorporation and WebMD's bylaws in effect on the date hereof, there are no
other agreements, arrangements, understandings, contracts, obligations or
liabilities between or among WebMD, Healtheon, Healtheon/WebMD, or any of their
respective subsidiaries or predecessor entities, on one hand, and McKesson,
HBOC, or any of their respective subsidiaries or predecessor entities, on the
other hand.

         4.2. REPRESENTATIONS AND WARRANTIES OF MCKHBOC. Each of McKesson and
HBOC represents and warrants to WebMD, Healtheon and Healtheon/WebMD as follows:

              4.2.1. Organization and Standing. Each of McKesson and HBOC is a
corporation duly organized, validly existing and in good standing under the laws
of the jurisdiction of its incorporation and has all necessary power and
authority: (i) to conduct its business in the manner in which its business is
currently being conducted; (ii) to own and use its assets in the manner in which
its assets are currently owned and used; and (iii) to perform its obligations
under this Agreement. Each of McKesson and HBOC is qualified to do business as a
foreign corporation, and is in good standing, under the laws of all
jurisdictions where the nature of its business requires such qualification and
where the failure to so qualify would result in any change, event, violation,
inaccuracy, circumstance or effect that is materially adverse to the business,
assets (including intangible assets), financial condition or results of
operations of McKesson or HBOC, as applicable, taken as a whole with its
subsidiaries.

              4.2.2. Authorization; Enforceability. All action on the part of
McKHBOC necessary for the authorization, execution, delivery and performance of
all obligations of McKHBOC under this Agreement or any document contemplated
hereby has been taken. This Agreement, when executed and delivered by each of
McKesson and HBOC, will constitute the valid and binding obligation of McKesson
and HBOC and is enforceable against each of them in accordance with its terms,
except as enforceability may be limited by bankruptcy, insolvency or other laws
affecting the enforcement of creditors' rights generally, and except that the
availability of the remedy of specific performance or other equitable relief is
subject to the discretion of the court before which any proceeding therefor may
be brought.

              4.2.3. No Other Agreements. Except as evidenced in this Agreement,
the Strategic Agreements, the Product Agreements, the WebMD Investment
Documents, the WebMD Restated Stockholders Agreement, the WebMD Shareholders
Agreement, WebMD's articles of incorporation and WebMD's bylaws in effect on the
date hereof, there are no other agreements, arrangements, understandings,
contracts, obligations or liabilities between or among WebMD, Healtheon,
Healtheon/WebMD or any of their respective subsidiaries or predecessor entities,
on one hand, and McKesson, HBOC or any of their subsidiaries or predecessor
entities, on the other hand.

              4.2.4. Experience; Investment. HBOC is acquiring the New Warrants
and the shares issuable upon exercise of the New Warrants solely for its own
account, not as a nominee or agent, and not with a view to, or for sale in
connection with, any distribution thereof, as that term is used under the
Securities Act. HBOC represents that it is an "accredited investor" within the
meaning of Rule 501(a)(3) of Regulation D promulgated by the Commission under
the Securities Act. In addition, HBOC represents that it relied upon no form of
general solicitation or general advertising from WebMD or its representatives in
connection with the issuance of the New Warrants, the Warrant Shares or other
securities.

              4.2.5. Registration under the Securities Act. McKHBOC understands
that: (a) neither the issuance of the New Warrants nor the shares issuable upon
exercise of the New Warrants has been 

                                       9

>PAGE>   10

registered under the Securities Act or applicable state securities laws, in
reliance upon exemptions from the registration provisions of the Securities Act
and applicable state securities laws, (b) the New Warrants or the Warrant Shares
received by HBOC must be held by it indefinitely unless the sale or transfer
thereof is subsequently registered under the Securities Act and applicable state
securities laws or an exemption from such registration is available, and the
certificates or documents representing the New Warrants and the Warrant Shares
will be legended to reflect such restrictions, (c) except as set forth in the
Registration Rights Agreement, WebMD is under no obligation to register any
Warrant Shares on HBOC's behalf or to assist it in complying with any exemption
from registration, and (d) the officers of WebMD will rely in part upon the
representations and warranties made by McKHBOC in this Agreement in order to
establish such exemption from the registration provisions of the Securities Act
and applicable state securities laws.

              4.2.6. Transfer. HBOC will not transfer any New Warrant or Warrant
Shares without registration under the Securities Act and applicable state
securities laws unless the transfer is exempt from registration under the
Securities Act and such laws.

         5.   MISCELLANEOUS.

         5.1. GOVERNING LAW. This Agreement shall be governed by and construed
under the laws of the State of Georgia, without regard to its principles of
conflicts of laws.

         5.2. SURVIVAL. The representations, warranties, covenants and
agreements made herein shall survive any investigation made by any party hereto
and the closing of the transactions contemplated hereby.

         5.3. ASSIGNMENT. This Agreement may not be assigned by any party
hereto. Notwithstanding the foregoing, (i) with the express written consent of
WebMD, which consent shall not be unreasonably withheld, McKHBOC may assign its
rights and obligations pursuant to Section 1 in connection with a sale by
McKHBOC of all or substantially all of the assets of the McKHBOC subsidiary or
business unit to which those rights and obligations relate, (ii) with the
express written consent of McKHBOC, which consent shall not be unreasonably
withheld, WebMD may assign its rights and obligations pursuant to Section 1 in
connection with a sale of all or substantially all of the assets of WebMD or the
WebMD subsidiary or business unit to which those rights and obligations relate,
(iii) this Agreement may be assigned by WebMD, without the consent of McKesson,
to either Healtheon or Healtheon/WebMD upon the Healtheon-WebMD Closing, and
(vi) this Agreement may be assigned by McKesson or HBOC to a directly or
indirectly wholly owned subsidiary of McKesson or HBOC, provided that McKesson
or HBOC, as applicable, shall remain primarily liable for all of its obligations
hereunder.

         5.4. ENTIRE AGREEMENT; AMENDMENT. This Agreement and the other
documents delivered pursuant hereto constitute the full and entire understanding
and agreement among the parties with regard to the subjects hereof and thereof.
Neither this Agreement nor any term hereof may be amended, waived, discharged or
terminated except by a written instrument signed by McKesson, HBOC and a
representative of WebMD so authorized by its Board of Directors.

         5.5. NOTICES. All notices and other communications required or
permitted hereunder shall be given in writing and shall be deemed effectively
given upon personal delivery or three (3) business days following deposit with
the United States Postal Service, by certified mail, return receipt requested,
postage prepaid, or otherwise delivered by hand or by messenger, as follows:


                                       10

>PAGE>   11

         If to WebMD:         WebMD, Inc.
                              400 The Lenox Building
                              3399 Peachtree Road
                              Atlanta, Georgia 30326
                              Attention: W. Michael Heekin, Esq.

         With a copy to:      Nelson Mullins Riley & Scarborough, L.L.P.
                              Bank of America Corporate Center
                              Suite 2600
                              100 North Tryon Street
                              Charlotte, North Carolina 28202
                              Attention: H. Bryan Ives III, Esq.
                                         C. Mark Kelly, Esq.

         If to Healtheon or
         Healtheon/WebMD:     Healtheon Corporation
                              4600 Patrick Henry Road
                              Santa Clara CA 95054
                              Attention: Jack Dennison, Esq.

         With a copy to:      Wilson, Sonsini, Goodrich & Rosati
                              650 Page Mill Road
                              Palo Alto, CA 94304-1050
                              Attention: Larry W. Sonsini, Esq.
                                         Martin W. Korman, Esq.
                                         Daniel R. Mitz, Esq.

         If to McKHBOC:       McKesson HBOC, Inc.
                              One Post Street
                              San Francisco, California 94104
                              Attention:  General Counsel

         With a copy to:      Jones, Day, Reavis & Pogue
                              3500 SunTrust Plaza
                              303 Peachtree Street
                              Atlanta, Georgia 30308-3242
                              Attention: Robert W. Smith, Esq.

                                          and

                              Skadden, Arps, Slate, Meagher & Flom LLP
                              525 University Avenue, Suite 220
                              Palo Alto, CA 94301
                              Attention:  Kenton J. King, Esq.

or at such other address as any party shall have furnished to the other parties
in writing.


                                       11

>PAGE>   12

         5.6.  AGENT'S FEES. Each party (i) represents and warrants that it has
retained no finder or broker in connection with the transactions contemplated by
this Agreement (except, in the case of McKHBOC, for Goldman Sachs, or as
otherwise disclosed to the other party hereto as of the date hereof), and (ii)
hereby agrees to indemnify and to hold the other party harmless of and from any
liability for commissions or compensation in the nature of an agent's, finder's
or broker's fee to any broker or other person or firm (and the cost and expenses
of defending against such liability or asserted liability) for which said party
is responsible.

         5.7.  EXPENSES. Each party shall bear its own expenses and legal fees
(and expenses and disbursements of its legal counsel) incurred on its behalf
with respect to this Agreement and the transactions contemplated hereby.

         5.8.  CONSTRUCTION OF CERTAIN TERMS. The titles of the articles,
sections, and subsections of this Agreement are for convenience of reference
only and are not to be considered in construing this Agreement.

         5.9.  COUNTERPARTS. This Agreement may be executed in any number of
counterparts, each of which shall be an original, but all of which together
shall constitute one instrument.

         5.10. ENFORCEMENT.

               5.10.1. Remedies at Law or in Equity. If WebMD or McKHBOC shall
default in any of its obligations under this Agreement or if any representation
or warranty made by or on behalf of such party in this Agreement or in any
certificate, report or other instrument delivered under or pursuant to any term
hereof shall be untrue or misleading in any material respect as of the date of
this Agreement or as of the date it was made, furnished or delivered, McKHBOC or
WebMD, respectively, may proceed to protect and enforce its rights by suit in
equity or action at law, whether for the specific performance of any term
contained in this Agreement, injunction against the breach of any such term or
in furtherance of the exercise of any power granted in this Agreement, or to
enforce any other legal or equitable right of such party or to take any one of
more of such actions.

               5.10.2. Remedies Cumulative; Waiver. No remedy referred to herein
or in any exhibit hereto is intended to be exclusive, but each shall be
cumulative and in addition to any other remedy referred to above or otherwise
available to a party at law or in equity. No express or implied waiver by any
party of any default shall be a waiver of any future or subsequent default. The
failure or delay of any party in exercising any rights granted it hereunder
shall not constitute a waiver of any such right and any single or partial
exercise of any particular right by such party shall not exhaust the same or
constitute a waiver of any other right provided herein.

         5.11. TIMELY PERFORMANCE. Time is of the essence as to the performance
of the obligations required of the respective parties under this Agreement.

         5.12. NO JOINT VENTURE. Nothing in this Agreement shall be deemed to
constitute WebMD and McKHBOC as partners, agents or joint venturers.

         5.13. SEVERABILITY. In the event any one or more of the provisions
contained in this Agreement should be held invalid, illegal or unenforceable in
any respect, the validity, legality and enforceability of the remaining
provisions contained herein shall not in any way be affected or impaired
thereby. The parties shall endeavor in good faith negotiations to replace the
invalid, illegal or


                                       12
>PAGE>   13


unenforceable provisions with valid provisions the economic effect of which
comes as close as possible to that of the invalid, illegal or unenforceable
provisions.




                      [SIGNATURES FOLLOW ON THE NEXT PAGE]



                                       13
>PAGE>   14


         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed as of the date and year first above written.


                                   WEBMD, INC.


   
                                   By: /s/ W. Michael Heekin
                                      -----------------------------------------
                                      Its: W. Michael Heekin
                                           Exec. VP


                                   MCKESSON HBOC, INC.


                                   By: /s/ David L. Mahoney
                                      -----------------------------------------
                                      Its: Co-Chief Executive Officer



                                   HBO & COMPANY


                                   By: /s/ Heidi Yodiesty
                                      -----------------------------------------
                                      Its: Chief Financial Officer



                                   For purposes of Section 2.1, Section 2.2,
                                   Section 2.3, Section 3.2, Section 3.4,
                                   Section 3.6 and Section 4.1 of this
                                   Agreement only:


                                   HEALTHEON CORPORATION


                                   By: /s/ W. Michael Long
                                      -----------------------------------------
                                      Its:



                                   HEALTHEON/WEBMD CORPORATION


                                   By: /s/ W. Michael Long
                                      -----------------------------------------
                                      Its:
    



                                       14

>PAGE>   15


                                   EXHIBIT 1.1

                           NEW STRATEGIC ARRANGEMENTS

         1.1.1 CONTINUING OBLIGATIONS OF WEBMD

         Notwithstanding the termination of the Strategic Agreements, the
parties hereby agree that WebMD shall continue to have the following obligations
hereunder:

         (a) WebMD shall provide a direct link to McKesson's online General
Medical-medical/surgical supply catalog and the functionality provided with
respect thereto by McKesson's web server from a WebMD web site on a nonexclusive
basis. Such access shall be implemented via a link which is at least as
prominent as that on which any other medical/surgical supplier appears on
WebMD's web site, to applications running on web servers operated by or for
McKHBOC, and shall not require that any McKHBOC applications be present on WebMD
servers. If there are no other links to medical/surgical suppliers on any WebMD
web site, then the McKesson medical/surgical link shall be on the highest level
on which links to other third party electronic commerce activities appear on
WebMD's web site. The parties understand and agree that in addition to
medical/surgical supplies, the General Medical catalog includes a limited number
of pharmaceuticals. To the extent that, after the date hereof, the
pharmaceuticals offered by McKHBOC through that catalog exceed to any material
extent the nature and scope of the pharmaceuticals currently offered by McKesson
through that catalog, WebMD shall not be obligated to offer such pharmaceuticals
through its direct link to the extent of such excess.

         (b) The access described above shall be provided without charge to
McKHBOC, until the earlier of December 31, 2000 or one (1) year after the
consummation of the transactions contemplated by the Healtheon-WebMD
Reorganization Agreement. Thereafter, provided that WebMD is charging third
parties for allowing such access to their products or services on WebMD web
sites, in the event McKHBOC elects to continue such access, WebMD may charge
McKHBOC a fee for allowing such access in an amount no less favorable, and on no
less favorable terms, than those offered by WebMD to any other distributor
offering products or services similar to those offered by McKHBOC through the
link provided hereunder.

         (c) Notwithstanding the foregoing, in the event that a WebMD customer
requests in writing that McKHBOC products or services be blocked from the
customer's co-branded version of any WebMD web site, WebMD shall be permitted to
comply with such request ten (10) business days after providing written notice
thereof to McKHBOC, which notice shall include a copy of the customer's written
request for blocking.

         (d) To the extent that WebMD has developed prior to the date hereof any
applications, including any technology specific thereto, used to effect the web
access described in Section 1.1.1(a) for McKHBOC products and services, (i)
McKHBOC shall have a royalty-free right and license to use such applications,
and (ii) to the extent such applications were developed based on McKHBOC's
proprietary information, McKHBOC shall have a perpetual, royalty-free and
exclusive (even as to the licensor) right and license to use such applications.

         (e) WebMD acknowledges and agrees that, as between McKHBOC and WebMD,
McKHBOC owns the data for all transactions between McKHBOC and its customers or
potential customers (whether or not they originate on a WebMD site); provided,
however, that WebMD shall



>PAGE>   16

continue to have the right to use any WebMD member identification data for
internal administrative purposes, including, but not limited to, authentication
of such members and ,provided further, that any data necessary for purposes of
determining charges pursuant to Section 1.1.1(b) above may be used by WebMD for
such purpose.

         (f) The total amount expended by WebMD to the date hereof to web-enable
McKHBOC products and services pursuant to paragraph 3(b) of the January Letter
Agreement is $1 million (the "AMOUNT EXPENDED"). The difference between WebMD's
$5 million commitment under said paragraph and the Amount Expended shall be
referred to hereinafter as the "DEVELOPMENT CREDIT." As of the date this
Agreement is entered into, whether or not the Reorganization is completed,
McKHBOC hereby releases WebMD from any further obligation to fund development
under such paragraph, in consideration of WebMD's agreement to offset the
Development Credit against the amount expended by WebMD under the Product
Agreements, as described in Section 1.1.1(a) hereof.

         (g) Upon the execution of this Agreement, McKHBOC shall pay to WebMD an
amount equal to $3.6 million, less $117,000 (representing a credit for 325
subscriptions placed by McKHBOC) for a net amount under this paragraph (g) of
$3,483,000, in respect of McKHBOC's obligation pursuant to the Strategic
Agreements to sponsor certain WebMD subscriptions. After the date hereof and
upon presentation of reasonably satisfactory documentation, WebMD shall pay to
McKHBOC for each physician subscription to WebMD's products and services
obtained by McKHBOC prior to the date hereof (other than the 325 subscriptions
referenced and accounted for above) compensation at the rates specified and
subject to the terms and provisions contained in the Strategic Agreements.

         (h) The provisions of contained in Sections 1.1.1(a), (b), and (c) and
in clause 1.1.1(d)(i) of this Exhibit 1.1 shall terminate on the fifth
anniversary date of the Healtheon-WebMD Closing, or if there is no such closing,
on the fifth anniversary date of this Agreement; provided, however, if there are
any applications licensed under clause (d)(i) McKHBOC shall have the right to
continue to license such applications on terms no less favorable than those
offered to third parties for similar licensed applications.


                                     1.1-2
>PAGE>   17


                                   EXHIBIT 1.2

                            NEW PRODUCT ARRANGEMENTS


         1.2.1 REFUND. Upon the execution of this Agreement, McKHBOC shall
refund to WebMD an amount equal to: (i) $6 million, representing all payments by
WebMD to McKHBOC pursuant to such Product Agreements, less (ii) the Development
Credit. As a result of this Section 1.2.1 and Section 1.1.1 (f) and (g) the net
amount payable by McKHBOC to WebMD on the date hereof is $5,483,000, which shall
be paid by McKHBOC within one business day following the date hereof, by wire
transfer of immediately available funds pursuant to the wire transfer
instructions provided by WebMD to McKHBOC.

         1.2.2 PRODUCT LICENSE. McKHBOC hereby grants to WebMD a fully paid-up,
nonexclusive, worldwide, license (without the right to sublicense) for a term of
one year commencing on the date hereof to use the Clinical Reference Products,
in the form in which such Clinical Reference Products are manufactured and
distributed as of the date hereof, in connection with WebMD's operation of its
business, in an HTML or other Internet-enabled format. The foregoing license
includes no obligation by McKHBOC to provide any maintenance or support (whether
to WebMD or to customers of WebMD) for the Clinical Reference Products. Such
license shall be transferable only to WebMD's parent corporation or any direct
or indirect subsidiary of WebMD's parent corporation, or, with McKHBOC's written
consent (which shall not be unreasonably withheld) in connection with the sale
or other transfer of all or a significant portion of WebMD's business.

         1.2.3 TRADEMARK LICENSE. McKHBOC hereby grants to WebMD a fully
paid-up, nonexclusive, worldwide, license (without the right to sublicense) to
use McKHBOC's trademarks and service marks (including but not limited to
McKHBOC's brands, logos, and slogans) (collectively, the "MCKHBOC MARKS") solely
in connection with the product license set forth above. WebMD shall use the
McKHBOC Marks in accordance with reasonable guidelines established by McKHBOC
from time to time. WebMD shall comply with McKHBOC's reasonable requirements
concerning the nature and quality of the goods and services provided by WebMD
under the McKHBOC Marks. WebMD shall submit to McKHBOC copies of all materials
using the McKHBOC Marks for approval prior to using, distributing, or otherwise
publicly exhibiting such materials. WebMD shall not use any of the McKHBOC Marks
in any manner likely to confuse, mislead, or deceive the public. WebMD
acknowledges that WebMD's use of the McKHBOC Marks shall inure to the benefit of
McKHBOC, and that WebMD shall not acquire any rights in the McKHBOC Marks by
virtue of such use.

         1.2.4 INTELLECTUAL PROPERTY INDEMNIFICATION. McKHBOC agrees to
indemnify, defend and hold harmless WebMD from and against any claim asserted or
suit or proceeding brought against WebMD asserting that the Clinical Reference
Products, or any portion or use thereof, infringes a United States patent,
trademark, copyright or trade secret of a third party, provided McKHBOC is given
reasonably prompt notice of, and full and complete authority, information and
assistance in the defense of, such claim, suit or proceeding once presented to
WebMD in writing. McKHBOC shall not be responsible for the cost of any
settlement of any such claim, suit or proceeding made by WebMD without the
written consent of McKHBOC. In addition, and at the expense of McKHBOC, in the
event there has been or McKHBOC reasonably believes that there may be an
injunction issued that prohibits or restricts WebMD's use of the Clinical
Reference Products (or any portion thereof), McKHBOC may either procure for
WebMD the right to continue using the same, or replace or modify the same so
that it becomes non-infringing, provided that such modification or replacement
has the same functional

>PAGE>   18

characteristics as the allegedly infringing version. WebMD may engage its own
counsel, at its expense, to advise WebMD in connection with any such claim, suit
or proceeding. McKHBOC shall cooperate with WebMD and its counsel in such
activities. McKHBOC shall not be liable to WebMD under the terms of this Section
or otherwise to the extent any infringement, claim, suit or proceeding is based
upon the use of any Clinical Reference Product in violation of this Agreement or
arises from a customization of the Clinical Reference Products performed by
McKHBOC for WebMD based upon WebMD's ideas, designs or specifications, or
performed by WebMD.


                                     1.2-2
>PAGE>   19

                                   EXHIBIT 2.1

                                 FORM OF WARRANT

THIS WARRANT AND THE SHARES OF COMMON STOCK ISSUABLE UPON EXERCISE HEREOF HAVE
NOT BEEN REGISTERED UNDER THE FEDERAL SECURITIES ACT OF 1933, AS AMENDED, THE
GEORGIA SECURITIES ACT OF 1973, AS AMENDED, OR THE SECURITIES LAWS OF ANY OTHER
STATE. THIS WARRANT AND ANY OF SUCH SHARES MAY NOT BE SOLD, OFFERED FOR SALE,
PLEDGED, HYPOTHECATED, OR OTHERWISE TRANSFERRED IN THE ABSENCE OF REGISTRATION
UNDER SAID ACTS AND ALL OTHER APPLICABLE SECURITIES LAWS UNLESS AN EXEMPTION
FROM REGISTRATION IS AVAILABLE.


THIS WARRANT IS SUBJECT TO THE RESTRICTIONS ON EXERCISE AND TRANSFER CONTAINED
IN ARTICLE IV HEREOF.


                           WARRANT TO PURCHASE SHARES
                                       OF
                                  COMMON STOCK
                                       OF
                                   WEBMD, INC.


                       DATE OF ISSUANCE: ___________, 1999

         THIS CERTIFIES that, for value received, WebMD, Inc., a Georgia
corporation (the "COMPANY"), hereby grants to HBO & Company, a Delaware
corporation, or its registered assigns (the "HOLDER"), the right to purchase, at
any time and from time to time after the Initial Exercise Date and prior to the
Expiration Date, up to _____________ shares in the aggregate of its Common Stock
Series F, without par value per share (the "COMMON Stock"), subject to the terms
and conditions set forth herein. This warrant is hereinafter referred to as the
"WARRANT."


                                    ARTICLE I

                               CERTAIN DEFINITIONS

         For all purposes of this Warrant, unless the context otherwise
requires, the following terms shall have the following respective meanings:

         "ACT": the federal Securities Act of 1933, as amended, and the rules
and regulations of the Commission promulgated thereunder, all as the same shall
be in effect at the time.

         "COMMON STOCK":  as defined on the first page hereof.

         "COMMISSION": the Securities and Exchange Commission or any other
federal agency then administering the Act.


>PAGE>   20

         "COMPANY": WebMD, Inc., a Georgia corporation, located at 400 The Lenox
Building, 3399 Peachtree Road, Atlanta, Georgia, 30326.

         "DATE OF ISSUANCE": the issue date of this Warrant, as set forth on the
first page hereof.

         "EXERCISE PRICE":  $________ per Stock Unit.

         "EXPIRATION DATE": as defined in Article VII hereof.

         "FAIR MARKET VALUE":

         (a) in the case of securities for which a public market exists as to
the twenty (20) trading days preceding the date as of which valuation is
required, the average of (i) each day's closing prices regular way for such
securities as reported by the New York Stock Exchange, (ii) if such securities
are not traded on such Exchange, each day's closing sale price for such
securities as reported by the Nasdaq Stock Market, or (iii) if such securities
are not traded on such Exchange or Market, each day's closing prices regular way
for such securities as reported by a national securities exchange on which such
securities are traded or each day's mean of the closing bid and ask prices for
such securities as reported by Nasdaq, wherever the average trading volume over
such period is higher; and

         (b) in the case of securities for which no public market exists, an
amount equal to the current fair market value of such securities as determined
in good faith by the board of directors of the Company.

         "HOLDER":  as defined on the first page hereof.

         "INITIAL EXERCISE DATE": The earlier of (i) the filing of the Articles
of Amendment (as defined in the Agreement pursuant to which this Warrant was
issued) or (ii) September 21, 1999.

         "PERSON": any individual, corporation, partnership, limited liability
company, trust, unincorporated organization and any government, and any
political subdivision, instrumentality or agency thereof.

         "REGISTRATION RIGHTS AGREEMENT": Registration Rights Agreement dated as
of even date herewith between the Company and the Holder.

         "STOCK UNIT": one share of Common Stock, as such stock is constituted
on the Date of Issuance and thereafter the number of shares of Common Stock as
shall result from the adjustments specified in Article V.

         "WARRANT": as defined on the first page hereof.

         "WARRANT OFFICE":  as defined in Section 3.1.

         "WARRANT SHARES": the shares of Common Stock underlying the Stock Units
purchasable by the Holder upon the exercise of this Warrant.


                                     2.1-2

>PAGE>   21

                                   ARTICLE II

                               EXERCISE OF WARRANT

         2.1 METHOD OF EXERCISE. To exercise this Warrant, the Holder shall
deliver to the Company at the Warrant Office designated pursuant to Section 3.1,
(a) a Notice of Exercise substantially in the form attached hereto as Exhibit A
duly executed after the Initial Exercise Date by the Holder specifying the
number of Warrant Shares to be purchased, (b) payment of an amount equal to the
aggregate Exercise Price for all such Warrant Shares, which shall be made (i) in
cash or by certified or bank cashier's check payable to the order of the Company
or by wire transfer of immediately available funds, (ii) by delivery to the
Company of that number of shares of capital stock of the Company (not including
any Warrant Shares purchasable or purchased upon the exercise of this Warrant)
having a value computed based upon the then-current fair market value as
determined in good faith by the Company's Board of Directors equal to the then
applicable Exercise Price multiplied by the number of Warrant Shares being
purchased, (iii) by delivery (on a form prescribed by the Company) of an
irrevocable direction to a securities broker approved by the Company to sell all
or part of the Warrant Shares being purchased (provided that the Warrant Shares
may be freely sold by such broker) and to deliver all or a portion of such sales
proceeds to the Company in satisfaction of the Exercise Price, (iv) by delivery
of an irrevocable notice to the Company that the Holder is waiving and
relinquishing the right to purchase a specified number of Warrant Shares subject
to this Warrant which number is set forth in the notice, with a fair market
value as of the date of exercise equal to the Exercise Price, which fair market
value shall be equal to the fair market value of the underlying Warrant Shares
being relinquished minus the Exercise Price of such shares, and (c) this
Warrant. The number of Warrant Shares to be purchased in any exercise hereunder
shall be no fewer than [500,000, IN THE CASE OF THE WARRANT TO PURCHASE
1,837,417 SHARES OF COMMON STOCK AND THE WARRANT TO PURCHASE 2,783,965 SHARES
OF; AND 50,000, IN THE CASE OF THE WARRANT TO PURCHASE 66,667 SHARES OF COMMON
STOCK] or the total number of Warrant Shares available for purchase at the date
of exercise, whichever is less. The Company shall, as promptly as practicable,
and in any event within five (5) days thereafter, cause to be issued and
delivered to the Holder (or its nominee) or the transferee designated in the
Notice of Exercise a certificate or certificates representing the number of
Warrant Shares specified in the Notice of Exercise. The stock certificate or
certificates so delivered shall be in denominations of shares as may be
specified in said notice and shall be issued in the name of the Holder, subject
to the limitations on transfer contained elsewhere herein, or such other name as
shall be designated in said notice. At the time of delivery of the certificate
or certificates, appropriate notation shall be made on the Warrant Shares
Purchase Schedule attached to this Warrant designating the number of shares
purchased, and this Warrant shall then be returned to the Holder if this Warrant
has been exercised only in part. The Holder or transferee so designated in the
Notice of Exercise shall be deemed to have become the Holder of record of such
Warrant Shares for all purposes as of the close of business on the date on which
the Notice of Exercise is delivered to the Warrant Office, provided that an
amount equal to the aggregate Exercise Price and this Warrant shall have also
been delivered to the Company. The Company shall pay all expenses, taxes
(excluding capital gains and income taxes) and other charges payable in
connection with the preparation, issuance and delivery of stock certificates,
except that, in case stock certificates shall be registered in a name or names
other than the name of the Holder, funds sufficient to pay all stock transfer
taxes payable upon the issuance of stock certificates shall be paid by the
Holder promptly upon receipt of a written request of the Company therefor.

         2.2 SHARES TO BE FULLY PAID AND NON-ASSESSABLE. All Warrant Shares
issued upon the exercise of this Warrant and the payment therefor shall be
validly issued, fully paid, non-assessable and free from preemptive rights.


                                     2.1-3

>PAGE>   22

         2.3 NO FRACTIONAL SHARES TO BE ISSUED. The Company shall not be
required upon any exercise of this Warrant to issue a certificate representing
any fraction of a share of Common Stock. If any fraction of a share of Common
Stock would be deliverable upon exercise of this Warrant, the Company may, in
lieu of delivering such fraction of a share of Common Stock, make a cash payment
to the Holder in an amount equal to the same fraction of the Fair Market Value
per share determined as of the business day immediately preceding the date of
exercise of such Warrant.

         2.4 LEGEND ON WARRANT SHARES. Each certificate for Warrant Shares
issued upon exercise of this Warrant, unless at the time of exercise such shares
are registered under the Act, shall bear substantially the following legend (and
any additional legend required by any national securities exchanges upon which
such shares may, at the time of such exercise, be listed or under applicable
securities laws):

         "The securities represented by this certificate have not been
         registered under the federal Securities Act of 1933, as amended, or the
         Georgia Securities Act of 1973, as amended (the "Acts"), or the
         securities laws of any state. They may not be sold, transferred,
         assigned, pledged, hypothecated, encumbered, or otherwise disposed of
         unless, in the opinion of counsel reasonably acceptable to the issuer,
         such transfer would be pursuant to an effective registration statement
         under said Acts or pursuant to an exemption from such registration."

         Any certificate issued at any time in exchange or substitution for any
certificate bearing such legend (except a new certificate issued upon completion
of a public offering pursuant to a registration statement under the Act of the
securities represented thereby) shall also bear the above legend unless, in the
opinion of counsel to the Company, the securities represented thereby need no
longer be subject to the restrictions on transferability. In addition, the
provisions of Article IV shall be binding upon all subsequent holders of this
Warrant.

         2.5 ACKNOWLEDGMENT OF CONTINUING OBLIGATION. The Company shall, at the
time of any exercise of this Warrant in whole or in part, upon request of the
Holder, acknowledge in writing its continuing obligation to such holder in
respect of any rights to which the Holder shall continue to be entitled after
exercise in accordance with this Warrant; provided, however, that the failure of
the Holder to make any such request shall not affect the continuing obligation
of the Company to the Holder in respect of such rights.

                                   ARTICLE III

                       WARRANT OFFICE; TRANSFER, DIVISION
                           OR COMBINATION OF WARRANTS

         3.1. WARRANT OFFICE. The Company shall maintain an office for certain
purposes specified herein (the "WARRANT OFFICE"), which office shall initially
be the Company's location set forth in Article I hereof, and may subsequently be
such other office of the Company, of any transfer agent of the Common Stock or
of any option or warrant administrator regularly engaged by the Company, in each
case within the continental United States as to which written notice has
previously been given to all of the Holders of the Warrants.


                                     2.1-4

>PAGE>   23

         3.2. OWNERSHIP OF WARRANT. The Company may deem and treat the Person in
whose name this Warrant is registered as the Holder and owner hereof
(notwithstanding any notations of ownership or writing hereon made by anyone
other than the Company) for all purposes and shall not be affected by any notice
to the contrary, until presentation of this Warrant for registration of transfer
as provided in this Article III.

         3.3. TRANSFER OF WARRANT. The Company agrees to maintain at the Warrant
Office books for the registration of permitted transfers of this Warrant.
Subject to the provisions of Article IV, this Warrant and all rights hereunder
are transferable, in whole or in part, on the books at that office, upon
surrender of this Warrant at that office, together with a written assignment of
this Warrant duly executed by the Holder or his, her or its duly authorized
agent or attorney and funds sufficient to pay any transfer taxes payable upon
the making of the transfer. Subject to Article IV, upon surrender and payment,
the Company shall execute and deliver a new Warrant in the name of the assignee,
noting thereon the number of Warrant Shares theretofore purchased under this
Warrant, and this Warrant shall promptly be canceled. To the extent this Warrant
is transferred in part, the Company shall execute and deliver a new Warrant in
the name of the Holder for the balance of the Warrant Shares not transferred to
the assignee. A Warrant may be exercised by a new Holder for the purchase of
shares of Common Stock without having a new warrant issued.

         3.4. DIVISION OR COMBINATION OF WARRANTS. Except as provided in Section
3.3 above, this Warrant may not be divided or combined with any other warrant.

         3.5. EXPENSES OF DELIVERY OF WARRANTS. The Company shall pay all
expenses, taxes (other than transfer taxes), and other charges payable in
connection with the preparation, issuance and delivery of new Warrants
hereunder.

                                   ARTICLE IV

                      RESTRICTIONS ON EXERCISE AND TRANSFER

         4.1. RESTRICTIONS ON EXERCISE AND TRANSFER. Notwithstanding any
provisions contained in this Warrant to the contrary, this Warrant shall not be
exercisable or transferable except upon the conditions specified in this Article
IV, which conditions are intended, among other things, to insure compliance with
the provisions of the Act in respect of the exercise or transfer of the Warrant.
The Holder, by acceptance hereof, agrees that he, she or it will not exercise or
transfer this Warrant prior to delivery to the Company of any required opinion
of the Holder's counsel (as the opinion and counsel are described in Section 4.2
hereof).

         4.2. OPINION OF COUNSEL. In connection with any exercise or transfer of
this Warrant, the following provisions shall apply:

              4.2.1. If, in the written opinion of counsel to the Holder (which
opinion and counsel must be reasonably acceptable to the Company), the proposed
exercise or transfer of this Warrant may be effected without registration of
this Warrant or the Common Stock issuable hereunder under the Act, the Holder
shall be entitled to exercise or transfer this Warrant as proposed. In no event
shall the Company be obligated (i) to effect a registration under the Act or any
state securities law so as to permit the proposed exercise or transfer of this
Warrant, or (ii) to qualify to do business or to file a general consent to
service of process in any state or other jurisdiction where the Company has not
already done so; provided, however, that the Company shall have the obligation
to register the shares

                                     2.1-5

>PAGE>   24

of Common Stock issuable upon exercise of this Warrant on the terms set forth in
the Registration Rights Agreement.

                  4.2.2. If in the opinion of such counsel, the proposed
exercise or transfer of this Warrant may not be effected without registration of
this Warrant under the Act, the Holder shall not be entitled to exercise or
transfer this Warrant until registration is effective or until exercise or
transfer may be effected without registration, in the opinion of such counsel as
set forth in Section 4.2.1 above.

                                    ARTICLE V

                                   ADJUSTMENTS

         5.1. ADJUSTMENTS TO NUMBER OF STOCK UNITS. The number of shares of
Common Stock comprising a Stock Unit shall be subject to adjustment from time to
time as set forth in this Section 5.1.

                  5.1.1. Stock Dividends, Subdivision and Combination. In case
at any time or from time to time the Company shall:

                         (i)   take a record of the holders of its common stock
of any series for the purpose of entitling them to receive a dividend payable
in, or other distribution of, the capital stock of any series,

                         (ii)  subdivide its outstanding shares of common stock
of any series into a larger number of shares of common stock of any series, or

                         (iii) combine its outstanding shares of common stock of
any series into a smaller number of shares of common stock of any series;

then the number of shares of Common Stock comprising a Stock Unit immediately
after the happening of any such event shall be adjusted so as to consist of the
number of shares of Common Stock (or in the case of clause (i) above, the number
of shares of Common Stock or other capital stock) that a record holder of the
number of shares of Common Stock comprising a Stock Unit immediately prior to
the happening of such event would own or be entitled to receive after the
happening of such event. The adjustments required by this subsection shall be
made whenever and as often as any specified event requiring an adjustment shall
occur.

                  5.1.2. Certain Other Dividends and Distributions. In case at
any time or from time to time the Company shall take a record of the holders of
its common stock of any series for the purpose of entitling them to receive any
dividend or other distribution of

                         (i) cash (other than a cash distribution made as a
dividend payable out of the net earnings or net profits of the Company realized
during the year of such distribution or the last preceding year and accumulated
net earnings or net profits of the Company from the date hereof to the time of
such distribution, computed in accordance with generally accepted accounting
principles employed by the Board of Directors of the Company for purposes of
financial reports to shareholders of the Company), or

                         (ii) any evidences of its indebtedness, any shares of
its stock or any other securities or property of any nature whatsoever (other
than cash);


                                     2.1-6

>PAGE>   25

then at least five (5) business days prior to the record date to determine
shareholders entitled to receive such dividend or distribution, the Company
shall give notice of such proposed dividend or distribution to the Holder for
the purpose of enabling the Holder to exercise the same, and thereby participate
in such dividend or distribution.

                  5.1.3 Fractional Interests. In computing adjustments under
this section, fractional interests in Common Stock shall be taken into account
to the nearest one-thousandth of a share.

                  5.1.4. When Adjustment Not Required--Abandonment of Plan for
Dividend and the Like. If the Company shall take a record of the holders of its
common stock of any series for the purpose of entitling them to receive a
dividend or distribution or subscription or purchase rights and shall,
thereafter and before the distribution to shareholders thereof, legally abandon
its plan to pay or deliver such dividend, distribution, subscription or purchase
rights, then thereafter no adjustment shall be required by reason of the taking
of such record and any such adjustment previously made in respect thereof shall
be rescinded and annulled.

                  5.1.5. Reorganization, Reclassification, Merger, Consolidation
or Disposition of Assets. In case the Company shall reorganize its capital,
reclassify its capital stock, merge or consolidate into another corporation,
then the number of shares of stock purchasable upon exercise of this Warrant
shall be adjusted to consist of the number of shares of stock or other
securities that a record holder of the number of shares of Common Stock
purchasable upon exercise of this Warrant immediately prior to such event would
own or be entitled to receive immediately after such event. This provision shall
apply to the merger of the Company pursuant to the Healtheon-WebMD
Reorganization Agreement (as defined in the Agreement pursuant to which this
Warrant was issued) in the manner provided in the Agreement pursuant to which
this Warrant was issued.

         5.2. NOTICE TO HOLDER. Whenever the Company takes any action that
causes the composition of a Stock Unit to change under Sections 5.1, the Company
shall provide the Holder with written notice of such change and the number of
Warrant Shares for which this Warrant is or will become exercisable. Such notice
will be provided not more than ten (10) days after any such action has occurred.

                                   ARTICLE VI

                      ADDITIONAL NOTICES TO WARRANT HOLDER

         In addition to any other notice required hereunder, the Company shall
provide the Holder with a copy of any notice that the Company is required to
provide those Persons holding shares of Common Stock on the same date such
Persons receive such notice.

                                   ARTICLE VII

                                   EXPIRATION

         This Warrant shall continue in effect until the earlier of (the
"EXPIRATION DATE"): (i) the date on which the Warrant has been exercised or
canceled pursuant to the terms hereof with respect to all of the Warrant Shares,
and (ii) the fifth (5th) anniversary of the Date of Issuance.


                                     2.1-7

>PAGE>   26

                                  ARTICLE VIII

                                CERTAIN COVENANTS

         8.1. COVENANTS OF THE COMPANY. The Company has taken all action
necessary to authorize the issuance of this Warrant and the issuance of shares
of Common Stock upon exercise hereof. The Company covenants and agrees that it
will reserve and set apart and have at all times, free from preemptive rights, a
number of shares of authorized but unissued Common Stock or other securities
deliverable upon the exercise of this Warrant from time to time sufficient to
enable it at any time to fulfill all its obligations hereunder.

         8.2 COVENANTS OF THE HOLDER. In the event that the exercise of this
Warrant for Common Stock would require any filing by the Holder under the Hart
Scott Rodino Antitrust Improvements Act of 1976 or any successor law and rules
and regulations issued pursuant to that Act or any successor law (the "HSR
ACT"), then, before such exercise, either (i) the parties shall have been
granted early termination of the waiting period under the HSR Act, or (ii) the
applicable waiting period shall have expired without any agency having obtained
injunctive relief with respect to the exercise of this Warrant.


                                   ARTICLE IX

                                  MISCELLANEOUS

         9.1 ENTIRE AGREEMENT; GOVERNING LAW. This Warrant contains the entire
agreement between the Holder and the Company with respect to the purchase of the
Warrant Shares and supersedes all prior arrangements or understandings with
respect thereto. This Warrant shall be governed by and construed under the laws
of the State of Georgia, without regard to its principles of conflicts of laws.

         9.2 WAIVER AND AMENDMENT. Any term or provision of this Warrant may be
waived at any time by the party that is entitled to the benefits thereof, and
any term or provision of this Warrant may be amended or supplemented at any time
by agreement of the holder hereof and the Company, except that any waiver of any
term or condition, or any amendment or supplementation, of this Warrant must be
in writing. A waiver of any breach or failure to enforce any of the terms or
conditions of this Warrant shall not in any way affect, limit or waive a party's
rights hereunder at any time to enforce strict compliance thereafter with any
term or condition of this Warrant.

         9.3 ILLEGALITY. In the event that any one or more of the provisions
contained in this Warrant shall be determined to be invalid, illegal or
unenforceable in any respect for any reason, the validity, legality and
enforceability of any such provision in any other respect and the remaining
provisions of this Warrant shall not, at the election of the party for whom the
benefit of the provision exists, be in any way impaired.

         9.4 FILING OF WARRANT. A copy of this Warrant shall be filed in the
records of the Company.

         9.5 NOTICES. Any notice or other document required or permitted to be
given or delivered to the Holder shall be delivered personally, or sent by
certified or registered mail, to the Holder c/o

                                     2.1-8

>PAGE>   27

McKesson HBOC, Inc., One Post Plaza, San Francisco, California 94101, Attention:
General Counsel, or at any more recent address of which any Holder shall have
notified the Company in writing. Any notice or other document required or
permitted to be given or delivered to the Company shall be delivered at, or sent
by certified or registered mail to, the Warrant Office, attention: Chief
Executive Officer, or such other address within the United States of America as
shall have been furnished by the Company to the Holder hereof.

         9.6 LIMITATION OF LIABILITY; NOT SHAREHOLDERS. No provision of this
Warrant shall be construed as conferring upon the Holder the right to vote,
consent, receive dividends or receive notice other than as herein expressly
provided in respect of meetings of shareholders for the election of directors of
the Company or any other matter whatsoever as a shareholder of the Company. No
provision hereof, in the absence of affirmative action by the Holder to purchase
Warrant Shares, and no enumeration herein of the rights or privileges of the
Holder, shall give rise to any liability of such Holder for the purchase price
of any Warrant Shares or as a shareholder of the Company, whether such liability
is asserted by the Company or by creditors of the Company.

         9.7 LOSS, DESTRUCTION, ETC. OF WARRANT. Upon receipt of evidence
satisfactory to the Company of the loss, theft, mutilation or destruction of the
Warrant, and in the case of any such loss, theft or destruction, upon delivery
of a bond of indemnity in such form and amount as shall be reasonably
satisfactory to the Company, or in the event of such mutilation, upon surrender
and cancellation of the Warrant, the Company shall make and deliver a new
warrant, of like tenor, in lieu of such lost, stolen, destroyed or mutilated
Warrant. Any Warrant issued under the provisions of this Section 9.7 in lieu of
any Warrant alleged to be lost, destroyed or stolen, or in lieu of any mutilated
Warrant, shall constitute an original contractual obligation on the part of the
Company.



                      [SIGNATURES FOLLOW ON THE NEXT PAGE]



                                     2.1-9
>PAGE>   28


         IN WITNESS WHEREOF, the Company has caused this Warrant to be signed in
its name by its Chief Executive Officer and its corporate seal to be impressed
hereon as of the ___ day of ______, 1999.


[CORPORATE SEAL]                          WEBMD, INC.

Attest:

By:                                       By:        
   -----------------------------             ---------------------------------
Name:                                          Jeffrey T. Arnold
     ---------------------------               Its: Chief Executive Officer
Title:                          
      --------------------------


                                     2.1-10
>PAGE>   29


                        WARRANT SHARES PURCHASE SCHEDULE


>TABLE>
>CAPTION>
NO. OF SHARES PURCHASED                         DATE OF PURCHASE                 NOTATION BY COMPANY OFFICER
>S>                                         >C>                              >C> 
--------------------------------------      --------------------------       -----------------------------------------


--------------------------------------      --------------------------       -----------------------------------------


--------------------------------------      --------------------------       -----------------------------------------


--------------------------------------      --------------------------       -----------------------------------------


--------------------------------------      --------------------------       -----------------------------------------


--------------------------------------      --------------------------       -----------------------------------------
>/TABLE>



                                     2.1-11
>PAGE>   30


                                    EXHIBIT A

                               NOTICE OF EXERCISE

                                                  Dated:
                                                        -----------------------

The undersigned hereby irrevocably elects to exercise its right to purchase
_____ shares of the Common Stock, no par value per share, of WebMD, Inc., such
right being pursuant to a Warrant dated _____________, 1999, as issued to HBO & Company, for up to ___________ shares of Common Stock (subject to adjustment in
accordance with the terms of the Warrant), and remits herewith the sum of
$_______ in payment for same in accordance with said Warrant. After giving
effect to the foregoing election to exercise, there shall remain unexercised the
right to purchase ________ shares of the Common Stock, no par value per share
(subject to adjustment), under this Warrant.


INSTRUCTIONS FOR REGISTRATION OF COMMON STOCK

Name
     -------------------------------------------------------------------------
                    (Please typewrite or print in block letters)

Address
       -----------------------------------------------------------------------

Signature:
          --------------------------------------------------------------------

Shares Heretofore Purchased
Under Warrant:



-----------------------------------



                                     2.1-12
>PAGE>   31


                                   EXHIBIT 2.3

                      FORM OF REGISTRATION RIGHTS AGREEMENT


                                   WEBMD, INC.
                          REGISTRATION RIGHTS AGREEMENT


         This REGISTRATION RIGHTS AGREEMENT (the "AGREEMENT") is made and
entered into as of the ____ day of ______, 1999, between WebMD, Inc., a Georgia
corporation (the "COMPANY"), and HBO & Company, a Delaware corporation ("HBOC").

                                    RECITALS:

         A. HBOC is the holder of three Warrants entitling the holder thereof to
purchase an aggregate of 4,688,049 shares of the Company's Series F Common Stock
pursuant to an Agreement dated as of the date hereof among the Company, McKesson
HBOC, Inc., a Delaware corporation, HBOC, Healtheon Corporation, a Delaware
corporation ("HEALTHEON"), and Healtheon/WebMD Corporation, a Delaware
corporation ("HEALTHEON/WEBMD").

         B. HBOC is also the holder of 1,117,000 shares of the Company's Series
A Preferred Stock, 650,000 shares of the Company's Series B Preferred Stock,
679,588 shares of the Company's Series F Preferred Stock and on November 22,
1999, will be entitled to receive an additional 50,000 shares of Series A
Preferred Stock and 19,230 shares of Series F Preferred Stock if the Company has
not completed an initial public offering (collectively, the "PREFERRED STOCK").

         C The Company and HBOC desire to set forth the registration rights to
be granted by the Company to HBOC.

         NOW, THEREFORE, in consideration of the mutual promises,
representations, warranties, covenants, and conditions set forth herein and in
the Agreement, the parties mutually agree as follows:


                                   AGREEMENT:

         1. CERTAIN DEFINITIONS. As used in this Agreement, the following terms
shall have the following respective meanings:

         "ARTICLES OF INCORPORATION" means the Amended and Restated Articles of
Incorporation of the Company as filed with the Secretary of State of the State
of Georgia, as amended from time to time.

         "COMMISSION" shall mean the Securities and Exchange Commission or any
other federal agency at the time administering the Securities Act.

         "COMMON STOCK" shall mean the voting common stock, without designation
as to series and without par value per share, of the Company and any and all
shares of capital stock or other equity securities of: (i) the Company which are
added to or exchanged or substituted for the Common Stock 


>PAGE>   32


by reason of the declaration of any stock dividend or stock split, the issuance
of any distribution or the reclassification, readjustment, recapitalization or
other such modification of the capital structure of the Company; (ii) any other
corporation, now or hereafter organized under the laws of any state or other
governmental authority, with which the Company is merged, which results from any
consolidation or reorganization to which the Company is a party, or to which is
sold all or substantially all of the shares or assets of the Company, if
immediately after such merger, consolidation, reorganization or sale, the
Company or any Stockholders of the Company own equity securities having in the
aggregate more than fifty percent (50%) of the total voting power of such other
corporation; or (iii) Healtheon Corporation, Healtheon/WebMD Corporation or
other entity the securities of which are issued in exchange for the Common Stock
of the Company pursuant to the Healtheon-WebMD Reorganization Agreement.

         "EXCHANGE ACT" shall mean the Securities Exchange Act of 1934, as
amended, and the rules and regulations of the Commission promulgated thereunder.

         "FAMILY MEMBER" shall mean (a) with respect to any individual, such
individual's spouse, any descendants (whether natural, adopted or in the process
of adoption), any trust all of the beneficial interests of which are owned by
any of such individuals or by any of such individuals together with any
organization described in Code Section 501(c)(3), the estate of any such
individual, and any corporation, association, partnership or limited liability
company all of the equity interests of which are owned by those above described
individuals, trusts or organizations and (b) with respect to any trust, the
owners of the beneficial interests of such trust.

         "FORM S-3" means such form under the Securities Act as in effect on the
date hereof or any registration form under the Securities Act subsequently
adopted by the Commission which permits inclusion or incorporation of
substantial information by reference to other documents filed by the Company
with the Commission.

         "HEALTHEON-WEBMD REORGANIZATION AGREEMENT" means the Agreement and Plan
of Reorganization dated May 20, 1999, by and among Healtheon, WebMD and Water
Acquisition Corp., a Georgia corporation.

         "HOLDER" shall mean HBOC or any of such Holder's respective successors
and assigns who acquire rights in accordance with this Agreement with respect to
the Registrable Securities directly or indirectly from such Holder.

         "INITIAL PUBLIC OFFERING" means the offer and sale by WebMD, Inc. of
shares of its Common Stock in a transaction underwritten by an investment
banking firm following the completion of which (i) the Common Stock will be
listed for trading on any national securities exchange or (ii) there will be at
least two market makers who are making a market in the Common Stock through the
Nasdaq National Market System.

         "INITIATING HOLDERS" shall mean any Holder or Holders of not less than
50% of the then outstanding Registrable Securities.

         The terms "REGISTER", "REGISTERED" and "REGISTRATION" refer to a
registration effected by preparing and filing a registration statement in
compliance with the Securities Act, and the declaration or ordering of the
effectiveness of such registration statement.


                                     2.3-2

>PAGE>   33

         "REGISTRABLE SECURITIES" means shares of Common Stock issuable upon
exercise of the Warrants, or upon the conversion of the Preferred Stock,
excluding in all cases, however (including exclusion from the calculation of the
number of outstanding Registrable Securities), any Registrable Securities sold
by a person in a transaction (i) pursuant to a registration statement under
Section 2 or 3 hereof or (ii) pursuant to Rule 144 (or any successor provision)
of the Securities Act.

         "SECURITIES ACT" shall mean the Securities Act of 1933, as amended, or
any similar federal statute promulgated in replacement thereof, and the rules
and regulations of the Commission thereunder, all as the same shall be in effect
at the time.

         "WARRANTS" shall mean the warrants to purchase an aggregate of up to
4,688,049 shares of Common Stock of the Company.

         2. DEMAND REGISTRATION. In the event that at any time after February
10, 2000, the Company shall receive from Initiating Holders a written request
that the Company effect a registration with respect to at least 1,000,000 shares
of Common Stock that constitute Registrable Securities (as adjusted for stock
splits, stock dividends, recapitalizations and similar events) the Company will:

         (a) promptly give written notice of the proposed registration to all
other Holders so they may have an opportunity to consider joining in such
registration, which they may do (subject to the terms and provisions of this
Agreement) at their election within ten (10) days after receipt of the notice of
the proposed registration by the Company; and

         (b) as soon as practicable, use its reasonable best efforts to effect
such registration (including, without limitation, the execution of an
undertaking to file post-effective amendments, appropriate qualification under
applicable blue sky or other state securities laws and appropriate compliance
with applicable regulations issued under the Securities Act) as may be so
requested and as would permit or facilitate the sale and distribution of all or
such portion of such Registrable Securities as are specified in such request,
together with all or such portion of the Registrable Securities of any Holder or
Holders joining in such request as are specified in a written request given
within ten (10) days after receipt of notice from the Company pursuant to
Section 2(a); provided that the Company shall not be obligated to take any
action to effect any such registration, qualification or compliance pursuant to
this Section 2:

             (i)   In any particular jurisdiction in which the Company would be
required to execute a general consent to service of process in effecting such
registration, qualification or compliance unless the Company is already subject
to service in such jurisdiction and except as may be required by the Securities
Act;

             (ii)  Prior to the date which is the earlier of (a) one hundred
eighty (180) days following the effective date of the registration statement
relating to an Initial Public Offering or (b) the release by the underwriters of
such offering of the related lock-up agreements;


                                     2.3-3

>PAGE>   34

             (iii) Within the one hundred twenty (120) day period immediately
following the effective date of a registration statement pertaining to a firm
commitment underwritten public offering of Common Stock for its own account or
for the account of a shareholder (including any Holder) of the Company who has
exercised a demand right to register shares of Common Stock (other than a
registration relating solely to a Commission Rule 145 transaction, a
registration relating solely to employee benefit plans, or a registration
statement on Form S-3 (or any similar short-form registration statement));

             (iv)  Within the sixty (60) day period immediately following the
effective date of a registration statement on Form S-3 (or any similar
short-form registration statement) pertaining to a firm commitment underwritten
public offering of Common Stock for its own account or for the account of
another shareholder of the Company who has exercised a demand right to register
shares of Common Stock (other than a registration relating solely to a
Commission Rule 145 transaction or a registration relating solely to employee
benefit plans); or

             (v)   After the Company has effected two (2) registrations pursuant
to this Section 2 and such registrations have been declared or ordered effective
and have remained effective for a period of at least ninety (90) consecutive
days.

         Subject to the foregoing clauses (i) through (v), the Company shall
file a registration statement covering the Registrable Securities so requested
to be registered as soon as practicable after receipt of the request of the
Initiating Holders. The Initiating Holders may, at any time prior to the
effective date of the registration statement relating to such registration,
revoke such request, without liability (except as set forth in Section 6 hereof)
to the Initiating Holders or any other Holders of Registrable Securities
requested to be registered pursuant to Section 2(a) hereof, by providing a
written notice to the Company revoking such request.

         Notwithstanding the above, the Company shall not be obligated to
effect, or to take any action to effect, any registration pursuant to this
Section 2 during the period starting with the date ninety (90) days prior to the
Company's good faith estimate of the date of filing of (or in the case of any
registration on Form S-3, forty-five (45) days prior), and ending on a date one
hundred twenty(120) days after the effective date of (or in the case of any
registration on Form S-3, sixty (60) days after), a Company-initiated
registration statement in connection with a bona fide firm commitment
underwritten registration for securities to be offered for the Company's own
account (the "INTENDED REGISTRATION"); provided that the Company is actively
employing in good faith all reasonable efforts to cause the Intended
Registration to become effective and provided further that the Company gives
notice to all Holders upon commencement of such period. The Holders shall be
entitled to exercise their rights pursuant to Section 4 hereof with respect to
an Intended Registration. An Intended Registration shall not be deemed to be a
demand registration of the Holders pursuant to this Section 2.

         (c) Underwriting. If the Holders propose an underwritten offering, the
sale of Registrable Securities pursuant to this Section 2 must be made by means
of a firm commitment underwriting through underwriters who are reasonably
acceptable to the Company and the holders of a majority of the Registrable
Securities that are proposed to be distributed through such underwriting. The
right of any Holder to registration pursuant to this Section 2 shall be
conditioned upon such Holder's participation in such underwriting and the
inclusion of such Holder's Registrable Securities in the underwriting to the
extent requested by such Holder (unless mutually otherwise agreed by a majority
in interest of the Holders and such Holder) to the extent provided herein.


                                     2.3-4

>PAGE>   35

         The Company and all Holders proposing to distribute Registrable
Securities through such underwriting shall enter into an underwriting agreement
in customary form with the underwriter or underwriters selected for such
underwriting. Notwithstanding any other provision of this Section 2(c), if the
underwriter determines that in its good faith view marketing factors require a
limitation of the number of shares to be underwritten and so advises the
Initiating Holders in writing, then the Initiating Holders shall so advise the
Company and all Holders (except those Holders who have indicated to the Company
their decision not to distribute any of their Registrable Securities through
such underwriting) and the number of Registrable Securities that may be included
in the registration and underwriting shall be allocated first to the Holders on
a pro rata basis according to the number of Registrable Securities requested to
be included by the Holders; second to the Company; and third to other
shareholders of the Company who have requested to sell in the registration. No
Registrable Securities excluded from the underwriting by reason of the
underwriter's marketing limitation shall be included in such registration. If at
least eighty percent (80%) of the Registrable Securities requested to be
registered by the Initiating Holders are not included in such registration, then
the Initiating Holders may request that the Company effect an additional
registration under the Securities Act of all or part of the Initiating Holders'
Registrable Securities in accordance with the provisions of this Section 2, and
the Company shall effect such additional registration.

         If any Holder disapproves of the terms of the underwriting, such person
may elect to withdraw therefrom by written notice to the Company, the
underwriter and the Initiating Holders. The Registrable Securities and/or other
securities so withdrawn from such underwriting shall also be withdrawn from such
registration; provided, however, that, if by the withdrawal of such Registrable
Securities a greater number of Registrable Securities held by other Holders may
be included in such registration (up to the maximum of any limitation imposed by
the underwriters), then the Company shall offer to all Holders who have included
Registrable Securities in the registration the right to include additional
Registrable Securities in the same proportion used above in determining the
underwriter limitation.

         If the underwriter has not limited the number of Registrable Securities
to be underwritten, the Company may include securities for its own account or
the account of others in such registration if the underwriter so agrees and if
the number of Registrable Securities which would otherwise have been included in
such registration and underwriting will not thereby be limited.

         (d) If the Company shall furnish to the Initiating Holders a
certificate signed by the President of the Company stating that, in the good
faith judgment of the Board of Directors of the Company, it would (because of
the existence of, or in anticipation of, any acquisition, financing activity, or
other transaction involving the Company, or the unavailability for reasons
beyond the Company's control of any required financial statements, disclosure of
information which is in its best interest not to publicly disclose, or any other
event or condition of similar significance to the Company) be seriously
detrimental to the Company and its shareholders for such registration statement
to be filed on or before the date filing would be required and it is therefore
essential to defer the filing of such registration statement, then the Company
may direct that such request for registration be delayed for a period not in
excess of ninety (90) days, such right to delay a request to be exercised by the
Company not more than twice in any twelve (12) month period.

         (e) Effective Registration Statement. A demand registration requested
pursuant to this Section 2 shall not be deemed to have been effected unless the
registration statement relating thereto (i) has become effective under the
Securities Act and any of the Registrable Securities of the Initiating Holders
included in such registration have actually been sold thereunder, and (ii) has
remained effective 

                                     2.3-5

>PAGE>   36

for a period of at least ninety (90) days (or such shorter period in which all
Registrable Securities included in such registration have actually been sold
thereunder).

         3. S-3 REGISTRATION. In case the Company shall receive from any Holder
or Holders a written request or requests that the Company effect a registration
on Form S-3 and any related qualification or compliance with respect to all or a
part of the Registrable Securities owned by such Holder or Holders, the Company
will:


         (a) promptly give written notice of the proposed registration, and any
related qualification or compliance, to all other Holders; and

         (b) as soon as practicable, and in any event within 30 days of the
receipt of such notice, file a registration statement on Form S-3 and effect all
other qualifications and compliances as may be so requested and as would permit
or facilitate the sale, distribution, transfer or hedging (through market
transactions using brokers, in a firm commitment underwriting, in negotiated
transactions or otherwise) of all or such portion of such Holder's or Holders'
Registrable Securities as are specified in such request, together with all or
such portion of the Registrable Securities of any other Holder or Holders
joining in such request as are specified in a written request given within 15
days after receipt of such written notice from the Company; provided, that the
Company shall not be obligated to effect any such registration, qualification or
compliance pursuant to this Section 3:

             (i)   if Form S-3 is not available for such offering by the 
Holders;

             (ii)  if the Holders, together with the holders of any other
securities of the Company entitled to inclusion in such registration, propose to
register Registrable Securities and such other securities (if any) at an
aggregate price to the public (net of any underwriters' discounts or
commissions) of less than $20 million;

             (iii) if the Company has, within the twelve (12) month period
preceding the date of such request, already effected three (3) registrations for
the Holders pursuant to this Section 3; or

             (iv)  in any particular jurisdiction in which the Company would be
required to qualify to do business or to execute a general consent to service of
process in effecting such registration, qualification or compliance.

         (c) Subject to the foregoing, the Company shall file a registration
statement covering the Registrable Securities and other securities so requested
to be registered as soon as practicable after receipt of the request or requests
of the Holders and shall keep it continuously effective until such Registrable
Securities have been sold pursuant thereto.

         (d) Notwithstanding the other provisions of this Section 3, the Company
shall have the right to delay the filing of any registration statement on Form
S-3 (an "S-3 REGISTRATION") otherwise required to be prepared and filed by the
Company pursuant to this Section 3, or to suspend the use of any S-3
Registration, for a period not in excess of 60 days (a "S-3 BLACKOUT PERIOD") if
the Company, in the good faith judgment of its Board of Directors, determines
(because of the existence of, or in anticipation of, any acquisition, financing
activity, or other transaction involving the Company, or the unavailability for
reasons beyond the Company's control of any required financial statements,

                                     2.3-6

>PAGE>   37

disclosure of information which is in its best interest not to publicly
disclose, or any other event or condition of similar significance to the
Company) that the registration and distribution of the Registrable Securities to
be covered by such S-3 Registration would be seriously detrimental to the
Company and its shareholders, provided that the S-3 Blackout Period shall
earlier terminate on the second business day following the completion or
abandonment of the relevant financing, acquisition or other transaction or upon
public disclosure by the Company or public admission by the Company of such
material nonpublic information or such time as such material nonpublic
information shall be publicly disclosed; and provided, further, that the Company
shall furnish to the Holders a certificate of an executive officer of the
Company to the effect that an event permitting a S-3 Blackout Period has
occurred (and no other reason need be given). The Company will promptly give the
Holders written notice of such determination and an approximation of the period
of the anticipated delay; provided, however, that the aggregate number of days
included in all S-3 Blackout Periods during any consecutive 12 months shall not
exceed 180 days. Each Holder agrees to cease all disposition efforts under such
S-3 Registration with respect to Registrable Securities held by such Holder
immediately upon receipt of notice of the beginning of any S-3 Blackout Period.
The Company shall provide written notice to the Holders of the end of each S-3
Blackout Period.

         4.  PIGGYBACK REGISTRATION.

         (a) If the Company shall determine to register for sale for cash any of
its Common Stock, for its own account or for the account of others (other than
the Holders), other than a registration relating solely to employee benefit
plans or securities issued or issuable to employees, consultants (to the extent
the securities owned or to be owned by such consultants could be registered on
Form S-8) or any of their Family Members (including a registration on Form S-8),
or a registration relating solely to a Commission Rule 145 transaction, a
registration on Form S-4 in connection with a merger, acquisition, divestiture,
reorganization or similar event, the Company promptly will give to each Holder
written notice thereof and shall use its reasonable best efforts to include in
such registration (and any related qualification under blue sky laws or other
compliance), and in any underwriting involved therein, all the Registrable
Securities specified in a written request or requests, made within ten (10) days
after receipt of such written notice from the Company, by any Holder or Holders.
However, the Company may, without the consent of the Holders, withdraw such
registration statement prior to its becoming effective if the Company has
abandoned its proposal to register the securities proposed to be registered
thereby.

         (b) Underwriting. If the registration of which the Company gives notice
is for a registered public offering involving an underwriting, the Company shall
so advise the Holders as a part of the written notice given pursuant to Section
4(a). In such event the right of any Holder to registration pursuant to Section
4(a) shall be conditioned upon such Holder's participation in such underwriting
and the inclusion of such Holder's Registrable Securities in the underwriting to
the extent provided herein. All Holders proposing to distribute their securities
through such underwriting shall (together with the Company and any other
shareholders of the Company distributing their securities through such
underwriting) enter into an underwriting agreement in customary form with the
underwriter or underwriters selected for such underwriting by the Company.
Notwithstanding any other provision of this Section 4(b), if the underwriter or
the Company determines that marketing factors require a limitation of the number
of shares to be underwritten, the underwriter may exclude some or all
Registrable Securities from such registration and underwriting. The Company
shall so advise all Holders (except those Holders who have indicated to the
Company their decision not to distribute any of their Registrable Securities
through such underwriting), and the number of shares of Registrable 

                                     2.3-7

>PAGE>   38

Securities that may be included in the registration and underwriting, if any,
shall be allocated among such Holders as follows:

                  (i) In the event of a piggyback registration pursuant to
Section 4(a) that is initiated by the Company, then the number of shares that
may be included in the registration and underwriting shall be allocated first to
the Company and then to all selling shareholders, including the Holders, who
have requested to sell in the registration on a pro rata basis according to the
number of shares requested to be included; and

                  (ii) In the event of a piggyback registration pursuant to
Section 4(a) that is initiated by the exercise of demand registration rights by
a shareholder or shareholders of the Company, then the number of shares that may
be included in the registration and underwriting shall be allocated first to
such selling shareholders who exercised such demand and then to all selling
shareholders, including the Holders, who have requested to sell in the
registration, on a pro rata basis according to the number of shares requested to
be included.

         (c) No Registrable Securities excluded from the underwriting by reason
of the underwriter's marketing limitation shall be included in such
registration. If any Holder disapproves of the terms of any such underwriting,
such person may elect to withdraw therefrom by written notice to the Company and
the underwriter. The Registrable Securities and/or other securities so withdrawn
from such underwriting shall also be withdrawn from such registration; provided,
however, that, if by the withdrawal of such Registrable Securities a greater
number of Registrable Securities held by other Holders may be included in such
registration (up to the maximum of any limitation imposed by the underwriters),
then the Company shall offer to all Holders who have included Registrable
Securities in the registration the right to include additional Registrable
Securities pursuant to the terms and limitations set forth herein in the same
proportion used above in determining the underwriter limitation.

         5. REGISTRATION PROCEDURES. In the case of each registration,
qualification or compliance effected by the Company pursuant to Section 2, 3 or
4 hereof, the Company will keep each Holder advised in writing as to the
initiation of each registration, qualification and compliance and as to the
completion thereof. At its expense, the Company will use its reasonable best
efforts to:

         (a) prepare and file with the Commission within ninety (90) days (or in
the case of any registration on Form S-3, thirty (30) days) after receipt of a
request for registration with respect to such Registrable Securities, a
registration statement on any form for which the Company then qualifies or which
counsel for the Company shall deem appropriate and which form shall be available
for the sale of the Registrable Securities in accordance with the intended
method(s) of distribution thereof, and use its best efforts to cause such
registration statement to become and remain effective; provided that before
filing with the Commission a registration statement or prospectus or any
amendments or supplements thereto, including documents incorporated by reference
after the initial filing of any registration statement, the Company shall (i)
furnish to the underwriters, if any, and to one (1) counsel selected by the
Holders of a majority of the Registrable Securities covered by such registration
statement copies of all such documents proposed to be filed, which documents
shall be subject to the review of the underwriters and such counsel, and (ii)
notify each Holder of Registrable Securities covered by such registration
statement of any stop order issued or threatened by the Commission and take all
reasonable actions required to prevent the entry of such stop order or to remove
it if entered;

         (b) prepare and file with the Commission such amendments and
supplements to such registration statement and the prospectus used in connection
therewith as may be necessary to keep such 

                                     2.3-8

>PAGE>   39

registration statement effective for a period of not less than ninety (90) days
or such shorter period which shall terminate when all Registrable Securities
covered by such registration statement have been sold (but not before the
expiration of the 90-day period referred to in Section 4(3) of the Securities
Act and Rule 174, or any successor thereto, thereunder, if applicable), and
comply with the provisions of the Securities Act with respect to the disposition
of all securities covered by such registration statement during such period in
accordance with the intended method(s) of disposition by the sellers thereof set
forth in such registration statement;

         (c) furnish, without charge, to each Holder and each underwriter, if
any, of Registrable Securities covered by such registration statement one (1)
signed copy of such registration statement, each amendment and supplement
thereto (including one (1) conformed copy to each Holder and one (1) signed copy
to each managing underwriter and in each case including all exhibits thereto),
and such number of copies of the prospectus included in such registration
statement (including each preliminary prospectus and any other prospectus filed
under Rule 424 under the Securities Act) as such Holders may request, in
conformity with the requirements of the Securities Act, and such other documents
as such Holder may reasonably request in order to facilitate the disposition of
the Registrable Securities owned by such Holder, but only while the Company
shall be required under the provisions hereof to cause the registration
statement to remain effective;

         (d) use its best efforts to register or qualify such Registrable
Securities under such other applicable securities or blue sky laws of such
jurisdictions as any Holder, and underwriter, if any, of Registrable Securities
covered by such registration statement reasonably requests as may be necessary
for the marketability of the Registrable Securities (such request to be made by
the time the applicable registration statement is deemed effective by the
Commission) and do any and all other acts and things which may be reasonably
necessary or advisable to enable such Holder and each underwriter, if any, to
consummate the disposition in such jurisdictions of the Registrable Securities
owned by such Holder; provided that the Company shall not be required to (i)
qualify generally to do business in any jurisdiction where it would not
otherwise be required to qualify but for this paragraph (d), (ii) subject itself
to taxation in any such jurisdiction, or (iii) consent to general service of
process in any such jurisdiction;

         (e) use its best efforts to cause the Registrable Securities covered by
such registration statement to be registered with or approved by such other
governmental agencies or authorities as may be necessary by virtue of the
business and operations of the Company to enable the Holder or Holders thereof
to consummate the disposition of such Registrable Securities;

         (f) immediately notify the managing underwriter, if any, and each
Holder of such Registrable Securities at any time when a prospectus relating
thereto is required to be delivered under the Securities Act of the happening of
any event which comes to the Company's attention if as a result of such event
the prospectus included in such registration statement contains an untrue
statement of a material fact or omits to state any material fact required to be
stated therein or necessary to make the statements therein not misleading and
the Company shall promptly prepare and furnish to such Holder a supplement or
amendment to such prospectus so that, as thereafter delivered to the purchasers
of such Registrable Securities, such prospectus shall not contain an untrue
statement of a material fact or omit to state any material fact required to be
stated therein or necessary to make the statements therein not misleading,
unless suspension of the use of such prospectus otherwise is authorized herein
or in the event of a S-3 Blackout Period, in which case no supplement or
amendment need be furnished;


                                     2.3-9

>PAGE>   40

         (g) use its best efforts to cause all such Registrable Securities
covered by the registration statement to be listed on the Nasdaq Stock Market or
the national securities exchange on which similar securities issued by the
Company are then listed, and enter into such customary agreements including a
listing application and indemnification agreement in customary form (provided
that the applicable listing requirements are satisfied), and to provide a
transfer agent and registrar for such Registrable Securities covered by such
registration statement no later than the effective date of such registration
statement;

         (h) enter into such customary agreements (including an underwriting
agreement in customary form) and take all such other actions as the Initiating
Holders or the underwriters retained by such Holders, if any, reasonably request
in order to expedite or facilitate the disposition of such Registrable
Securities, including customary indemnification;

         (i) make available for inspection during normal business hours by any
Holder of Registrable Securities covered by such registration statement, any
underwriter participating in any disposition pursuant to such registration
statement, and any attorney, accountant or other agent retained by any such
Holder or underwriter (collectively, the "INSPECTORS"), all financial and other
records, pertinent corporate documents and properties of the Company and its
subsidiaries (collectively, "RECORDS"), if any, as shall be reasonably necessary
to enable them to exercise their due diligence responsibility, and cause the
Company's and its subsidiaries' officers, directors and employees to supply all
information and respond to all inquiries reasonably requested by any such
Inspector in connection with such registration statement. Notwithstanding the
foregoing, the Company shall have no obligation to disclose any Records to the
Inspectors in the event the Company determines that such disclosure is
reasonably likely to have an adverse effect on the Company's ability to assert
the existence of an attorney-client privilege with respect thereto;

         (j) in the event that any contemplated public offering is underwritten,
use its best efforts to obtain a "comfort" letter from the Company's independent
public accountants in customary form and covering such matters of the type
customarily covered by "comfort" letters as the Holders of a majority (by number
of shares) of the Registrable Securities being sold reasonably request, and
provided that such request is reasonable in the underwriter's point of view;

         (k) use its best efforts to obtain an obtain an opinion of counsel from
the Company's counsel in customary form and covering such matters of the type
customarily covered in opinions of counsel in connection with such transactions;


                                     2.3-10

>PAGE>   41

         (l) comply, and continue to comply during the period that such
registration statement is effective under the Securities Act, in all material
respects with the Securities Act and the Securities Exchange Act of 1934 and
with all applicable rules and regulations of the Commission with respect to the
disposition of all securities covered by such registration statement, and make
available to its security holders, as soon as reasonably practicable, an
earnings statement covering the period of at least twelve (12) months, but not
more than eighteen (18) months, beginning with the first full calendar month
after the effective date of such registration statement, which earnings
statement shall satisfy the provisions of Section 11(a) of the Securities Act,
and not file any amendment or supplement to such registration statement or
prospectus to which Holder shall have reasonably objected on the grounds that
such amendment or supplement does not comply in all material respects with the
requirements of the Securities Act, having been furnished with a copy thereof at
least five (5) business days prior to the filing thereof; and

         (m) in the event the offering is underwritten, develop a presentation
reasonably acceptable to the underwriters to facilitate the offering and to make
its chief executive officer and chief financial officer available for
participation in such meetings and presentations (e.g., road show for the
offering) at such locations (including Europe) as the underwriter reasonably
requests.

Each Holder of Registrable Securities agrees that, upon receipt of any notice
from the Company of the happening of any event of the kind described in Section
5(f) hereof, such Holder shall discontinue disposition of Registrable Securities
pursuant to the registration statement covering such Registrable Securities
until such Holder's receipt of the copies of the supplemented or amended
prospectus contemplated by Section 5(f) hereof, and, if so directed by the
Company, such Holder shall deliver to the Company (at the Company's expense) all
copies (including, without limitation, any and all drafts), other than permanent
file copies, then in such Holder's possession, of the prospectus covering such
Registrable Securities current at the time of receipt of such notice. In the
event the Company shall give any such notice, the period mentioned in Section
5(b) hereof shall be extended by the greater of (i) ten (10) business days or
(ii) the number of days during the period from and including the date of the
giving of such notice pursuant to Section 5(f) hereof to and including the date
when each Holder of Registrable Securities covered by such registration
statement shall have received the copies of the supplemented or amended
prospectus contemplated by Section 5(f) hereof.

         6. RULE 144. Notwithstanding anything to the contrary contained herein,
no Holder shall have rights to a registration under Section 2, 3 or 4 hereof
after the time that such Holder could sell, within ninety (90) days, all of its
Registrable Securities pursuant to Rule 144(e) promulgated under the Securities
Act or any successor rule thereto; provided that the Company hereby agrees to
take the following actions to ensure the availability of Rule 144 to each such
Holder (or such similar actions as shall be required under any successor rule
thereto):

         (a) make and keep public information available as those terms are
understood and defined in Rule 144;

         (b) use its best efforts to file with the Commission in a timely manner
all reports and other documents required of the Company under the Securities Act
and the Exchange Act; and

         (c) so long as any Holder owns any Registrable Securities, furnish to a
Holder upon request, a written statement by the Company as to its compliance
with the reporting requirements of Rule 144 (at any time from and after ninety
(90) days following the effective date of the registration statement relating to
an Initial Public Offering), and of the Securities Act and the Exchange Act (at
any 

                                     2.3-11

>PAGE>   42

time after it has become subject to such reporting requirements), a copy of the
most recent annual or quarterly report of the Company, and such other reports
and documents so filed as the Holder may reasonably request.

         7. REGISTRATION EXPENSES. The Company shall pay all expenses in
connection with any registration, including, without limitation, all
registration, filing and NASD fees, printing expenses, all fees and expenses of
complying with securities or blue sky laws, the fees and disbursements of one
counsel for the Holders and the fees and disbursements of counsel for the
Company and of its independent accountants; provided that, in any registration,
each party shall pay for its own underwriting discounts and commissions and
transfer taxes. The Company shall not, however, be required to pay for expenses
of any registration proceeding begun pursuant to Section 2, 3 or 4 hereof, the
request of which has been subsequently withdrawn by the Initiating Holders
(unless the withdrawal is based upon material adverse information concerning the
Company of which the Initiating Holders were unaware at the time of such
request), in which case such expenses shall be borne by the Holders whose
securities were to be included in the registration in proportion to the number
of shares for which such registration was requested.

         8. ASSIGNMENT OF RIGHTS. Any Holder may assign its rights under this
Agreement to any party acquiring 2,400,000 shares or more of Registrable
Securities; provided, however, that a Holder may assign its rights under this
Agreement without such restrictions to a transferee or assignee that controls,
is controlled by or is under common control with such Holder.

         9. INFORMATION BY HOLDER. The Holder or Holders of Registrable
Securities included in any registration shall furnish to the Company such
information regarding such Holder or Holders and the distribution proposed by
such Holder or Holders as the Company may request in writing.

         10. "MARKET STAND OFF" AGREEMENT. Each Holder agrees not to sell or
otherwise transfer or dispose of any Common Stock (or other securities) of the
Company held by it during the 180 day period following the effective date of the
Initial Public Offering if so requested by the Company and underwriters of
Common Stock (or other securities) of the Company. The Company may impose stop
transfer instructions with respect to the shares (or securities) subject to the
foregoing restriction until the end of such period.

         11. INDEMNIFICATION.

         (a) In the event of the offer and sale of Registrable Securities held
by Holders under the 1933 Act, the Company shall, and hereby does, indemnify and
hold harmless, to the fullest extent permitted by law, each Holder, its
directors, officers, partners, each other person who participates as an
underwriter in the offering or sale of such securities, and each other Person,
if any, who controls or is under common control with such Holder or any such
underwriter within the meaning of Section 15 of the 1933 Act, against any
losses, claims, damages or liabilities, joint or several, and expenses to which
the Holder or any such director, officer, partner or underwriter or controlling
person may become subject under the 1933 Act or otherwise, insofar as such
losses, claims, damages, liabilities or expenses (or actions or proceedings,
whether commenced or threatened, in respect thereof) arise out of or are based
upon any untrue statement or alleged untrue statement of any material fact
contained in any registration statement under which such shares were registered
under the 1933 Act, any preliminary prospectus, final prospectus or summary
prospectus contained therein, or any amendment or supplement thereto, or any
omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein in light of the
circumstances in which they 

                                     2.3-12

>PAGE>   43

were made not misleading or any violation by the Company of any federal, state
or common law rule or regulation applicable to the Company and relating to
action required of or inaction by the Company in connection with any such
registration, and the Company shall reimburse the Holder, and each such
director, officer, partner, underwriter and controlling person for any legal or
any other expenses reasonably incurred by them in connection with investigating,
defending or settling any such loss, claim, damage, liability, action or
proceeding; provided that the Company shall not be liable in any such case to
the extent that any such loss, claim, damage, liability (or action or proceeding
in respect thereof) or expense arises out of or is based upon an untrue
statement or alleged untrue statement in or omission or alleged omission from
such registration statement, any such preliminary prospectus, final prospectus,
summary prospectus, amendment or supplement in reliance upon and in conformity
with written information furnished to the Company through an instrument duly
executed by or on behalf of such Holder specifically stating that it is for use
in the preparation thereof. Such indemnity shall remain in full force and effect
regardless of any investigation made by or on behalf of the Holders, or any such
director, officer, partner, underwriter or controlling person and shall survive
the transfer of such shares by the Holder.

         (b) The Company may require, as a condition to including any
Registrable Securities to be offered by a Holder in any registration statement
filed pursuant to this Agreement, that the Company shall have received an
agreement from such Holder to be bound by the terms of this Section 11,
including an undertaking reasonably satisfactory to it from such Holder, to
indemnify and hold the Company, its directors and officers and each other
Person, if any, who controls the Company within the meaning of Section 15 of the
1933 Act, against any losses, claims, damages or liabilities, joint or several,
to which the Company or any such director or officer or controlling person may
become subject under the 1933 Act or otherwise, insofar as such losses, claims,
damages or liabilities (or actions or proceedings, whether commenced or
threatened, in respect thereof) arise out of or are based upon any untrue
statement or alleged untrue statement in or omission or alleged omission from
such registration statement, any preliminary prospectus, final prospectus or
summary prospectus contained therein, or any amendment or supplement thereto, if
such statement or alleged statement or omission or alleged omission was made in
reliance upon and in conformity with written information about such Holder as a
Holder of the Company furnished to the Company through an instrument duly
executed by such Holder specifically stating that it is for use in the
preparation of such registration statement, preliminary prospectus, final
prospectus, summary prospectus, amendment or supplement; provided, however, that
such indemnity agreement found in this Section 11(b) shall in no event exceed
the gross proceeds from the offering received by such Holder. Such indemnity
shall remain in full force and effect, regardless of any investigation made by
or on behalf of the Company or any such director, officer or controlling person
and shall survive the transfer by any Holder of such shares.

         (c) Promptly after receipt by an indemnified party of notice of the
commencement of any action or proceeding involving a claim referred to in
Section 11(a) or (b) hereof (including any governmental action), such
indemnified party shall, if a claim in respect thereof is to be made against an
indemnifying party, give written notice to the indemnifying party of the
commencement of such action; provided that the failure of any indemnified party
to give notice as provided herein shall not relieve the indemnifying party of
its obligations under Section 11(a) or (b) hereof, except to the extent that the
indemnifying party is actually prejudiced by such failure to give notice. In
case any such action is brought against an indemnified party, unless in such
indemnified party's reasonable judgment a conflict of interest between such
indemnified and indemnifying parties may exist or the indemnified party may have
defenses not available to the indemnifying party in respect of such claim, the
indemnifying party shall be entitled to participate in and to assume the defense
thereof, with counsel reasonably satisfactory to such indemnified party and,
after notice from the indemnifying party to such 


                                     2.3-13

>PAGE>   44

indemnified party of its election so to assume the defense thereof, the
indemnifying party shall not be liable to such indemnified party for any legal
or other expenses subsequently incurred by the latter in connection with the
defense thereof, unless in such indemnified party's reasonable judgment a
conflict of interest between such indemnified and indemnifying parties arises in
respect of such claim after the assumption of the defenses thereof, other than
reasonable costs of investigation. Neither an indemnified nor an indemnifying
party shall be liable for any settlement of any action or proceeding effected
without its consent. No indemnifying party shall, without the consent of the
indemnified party, consent to entry of any judgment or enter into any settlement
which does not include as an unconditional term thereof the giving by the
claimant or plaintiff to such indemnified party of a release from all liability
in respect of such claim or litigation. Notwithstanding anything to the contrary
set forth herein, and without limiting any of the rights set forth above, in any
event any party shall have the right to retain, at its own expense, counsel with
respect to the defense of a claim.

         (d) The indemnification required by Section 11(a) and (b) hereof shall
be made by periodic payments of the amount thereof during the course of the
investigation or defense, as and when bills are received or expenses, losses,
damages or liabilities are incurred.

         (e) If the indemnification provided for in this Section 11 is held by a
court of competent jurisdiction to be unavailable to an indemnified party with
respect to any loss, liability, claim, damage or expense referred to herein, the
indemnifying party, in lieu of indemnifying such indemnified party hereunder,
shall contribute to the amount paid or payable by such indemnified party as a
result of such loss, liability, claim, damage or expense as is appropriate to
reflect the proportionate relative fault of the indemnifying party on the one
hand and the indemnified party on the other (determined by reference to, among
other things, whether the untrue or alleged untrue statement of a material fact
or omission relates to information supplied by the indemnifying party or the
indemnified party and the parties' relative intent, knowledge, access to
information and opportunity to correct or prevent such untrue statement or
omission), or (ii) if the allocation provided by clause (i) above is not
permitted by applicable law or provides a lesser sum to the indemnified party
than the amount hereinafter calculated, not only the proportionate relative
fault of the indemnifying party and the indemnified party, but also the relative
benefits received by the indemnifying party on the one hand and the indemnified
party on the other, as well as any other relevant equitable considerations. No
indemnified party guilty of fraudulent misrepresentation (within the meaning of
Section 11(f) of the Securities Act) shall be entitled to contribution from any
indemnifying party who was not guilty of such fraudulent misrepresentation.

         (f) Other Indemnification. Indemnification similar to that specified in
the preceding subsections of this Section 11 (with appropriate modifications)
shall be given by the Company and each Holder of Registrable Securities with
respect to any required registration or other qualification of securities under
any federal or state law or regulation or governmental authority other than the
Securities Act.

         12. MISCELLANEOUS.

         (a) Governing Law. This Agreement shall be governed by and construed in
accordance with the laws of the State of Georgia applicable to contracts between
Georgia residents entered into and to be performed entirely within the State of
Georgia.

         (b) Successors and Assigns. Except as otherwise provided herein, the
provisions hereof shall inure to the benefit of, and be binding upon, the
successors, assigns, executors and administrators of the parties hereto. In the
event the Company merges with, or is otherwise acquired by, a direct or 

                                     2.3-14

>PAGE>   45

indirect subsidiary of a publicly-traded company, the Company shall condition
the merger or acquisition on the assumption by such parent company of the
Company's obligations under this Agreement.

         (c) Entire Agreement. This Agreement constitutes the full and entire
understanding and agreement between the parties with regard to the subjects
hereof.

         (d) Notices, etc. All notices and other communications required or
permitted hereunder shall be given in writing and shall be deemed effectively
given upon personal delivery or three (3) business days following deposit with
the United States Postal Service, by certified mail, return receipt requested,
postage prepaid, or otherwise delivered by hand or by messenger, addressed: (a)
if to the HBOC, c/o McKesson HBOC, Inc., One Post Street, San Francisco,
California, 94104, Attention: General Counsel, with copies to Jones, Day, Reavis
& Pogue, 3500 SunTrust Plaza, 303 Peachtree Street, Atlanta, Georgia,
30308-3242, Attention: Robert W. Smith, Esq. and Skadden, Arps, Slate, Meagher & Flom LLP, 525 University Avenue, Palo Alto, California, 94301, Attention: Kenton
J. King, or (b) if to any other Holder of any Registrable Securities, at such
address as such holder shall have furnished the Company in writing, or, until
any such Holder so furnishes an address to the Company, then to and at the
address of the last Holder of such Registrable Securities who has so furnished
an address to the Company, or (c) if to the Company, at WebMD, Inc., 400 The
Lenox Building, 3399 Peachtree Road, Atlanta, Georgia 30326, Attention: General
Counsel, or at such other address as the Company shall have furnished to HBOC
and each such other Holder in writing.

         (e) Delays or Omissions. No delay or omission to exercise any right,
power or remedy accruing to any Holder of any Registrable Securities, upon any
breach or default of the Company under this Agreement, shall impair any such
right, power or remedy of such Holder nor shall it be construed to be a waiver
of any such breach or default, or an acquiescence therein, or of or in any
similar breach or default thereunder occurring; nor shall any waiver of any
single breach or default be deemed a waiver of any other breach or default
theretofore or thereafter occurring. Any waiver, permit, consent or approval of
any kind or character on the part of any Holder of any breach or default under
this Agreement, or any waiver on the part of any Holder of any provisions or
conditions of this Agreement, must be in writing and shall be effective only to
the extent specifically set forth in such writing. All remedies, either under
this Agreement, or by law or otherwise afforded to any holder, shall be
cumulative and not alternative.

         (f) Counterparts. This Agreement may be executed in any number of
counterparts, each of which shall be enforceable against the parties actually
executing such counterparts, and all of which together shall constitute one
instrument.

         (g) Severability. In the case any provision of this Agreement shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.

         (h) Amendments. The provisions of this Agreement may be amended at any
time and from time to time, and particular provisions of this Agreement may be
waived, with and only with an agreement or consent in writing signed by the
Company and by the holders of a majority of the number of shares of Registrable
Securities (or securities convertible into Registrable Securities) outstanding
as of the date of such amendment or waiver. HBOC acknowledges that by the
operation of this Section 10(h), the holders of a majority of the outstanding
Registrable Securities may have the right and power to diminish or eliminate all
rights of HBOC under this Agreement.



                                     2.3-15

>PAGE>   46

                      [SIGNATURES FOLLOW ON THE NEXT PAGE]


                                     2.3-16
>PAGE>   47


         IN WITNESS WHEREOF, the parties have executed and delivered this
Agreement as of the day and year first above written.



                                   WEBMD, INC.


                                   By:
                                      -----------------------------------------
                                      Its:





                                  HBO & COMPANY



                                  By:
                                     ------------------------------------------
                                     Its:


         The undersigned execute this Agreement for the purpose of acknowledging
that upon the consummation of the transactions contemplated by the
Healtheon-WebMD Reorganization Agreement either Healtheon Corporation or
Healtheon/WebMD Corporation, which ever shall be the acquiror under the
Healtheon-WebMD Reorganization Agreement, shall assume the obligations of WebMD,
Inc. under this Agreement.

                                  HEALTHEON CORPORATION


                                  BY:  
                                     ------------------------------------------
                                  TITLE:
                                        ---------------------------------------

                                  HEALTHEON-WEBMD CORPORATION


                                  BY:   
                                     ------------------------------------------
                                  TITLE:
                                        ---------------------------------------


                                     2.3-17
>PAGE>   48

                                   EXHIBIT 2.4


                              ARTICLES OF AMENDMENT

                  ARTICLES OF AMENDMENT TO AMENDED AND RESTATED
                    ARTICLES OF INCORPORATION OF WEBMD, INC.


         In accordance with Section 14-2-1003 of the Georgia Business
Corporation Code (the "Code"), WebMD, Inc. (the "Corporation"), a corporation
organized and existing under and by virtue of the Code, DOES HEREBY CERTIFY:

         1.       The name of the Corporation is WebMD, Inc.

         2.       Effective the date hereof, the first paragraph of Article Two
                  of the Amended and Restated Articles of Incorporation of the
                  Corporation is amended by deleting such paragraph in its
                  entirety and substituting therefore the following:

                                    "The total number of shares of all classes
                           which the Corporation has the authority to issue is
                           107,000,000, of which: (i) 70,000,000 shares of stock
                           are designated as Common Stock (without designation
                           as to series); (ii) 3,000,000 shares are designated
                           as Common Stock Series B; (iii) 1,500,000 shares are
                           designated as Common Stock Series C; (iv) 15,000,000
                           shares are designated as Common Stock Series D; (v)
                           2,500,000 shares are designated as Common Stock
                           Series E; (vi) 5,000,000 shares are designated as
                           Common Stock Series F; and (vii) 10,000,000 shares
                           are designated as Preferred Stock. The designations,
                           voting powers, preferences, relative rights,
                           qualifications, limitations and restrictions of or on
                           each class and series of stock are as follows:"

         3.       Effective the date hereof, Section A of Article Two of the
                  Amended and Restated Articles of Incorporation of the
                  Corporation is amended by deleting such paragraph in its
                  entirety and substituting therefore the following:

                           "A.      Common Stock

                                    The Corporation's authorized and issued
                           shares of Common Stock Series A are hereby renamed
                           "Common Stock," without designation as to series. The
                           Corporation is authorized to issue 70,000,000 shares
                           of Common Stock, without par value per share. Each
                           share of Common Stock shall be entitled to one vote.

                                    The Corporation is authorized to issue
                           3,000,000 shares of Common Stock Series B, without
                           par value per share. The Common Stock Series B shall
                           have rights that are identical to that of the Common
                           Stock, except that (i) shares of Common Stock Series
                           B shall have no

>PAGE>   49

                           voting rights except as may be otherwise required by
                           the Georgia Business Corporation Code, as amended
                           (the "Act"); and (ii) in the event of any
                           liquidation, dissolution or winding-up of the
                           Corporation, whether voluntary or involuntary,
                           holders of each share of Common Stock Series B,
                           Common Stock Series C and Common Stock Series E
                           shall be entitled to be paid first out of the assets
                           of the Corporation available for distribution to
                           holders of the Corporation's capital stock of all
                           classes or series, before any sums shall be paid or
                           any assets distributed among the holders of the
                           shares of Common Stock, Common Stock Series D or
                           Common Stock Series F, in an amount equal to
                           $0.285714 per share of Common Stock Series B.

                                    The Corporation is authorized to issue
                           1,500,000 shares of Common Stock Series C, without
                           par value per share. The Common Stock Series C shall
                           have rights that are identical to that of the Common
                           Stock, except that (i) shares of Common Stock Series
                           C shall have no voting rights except as may be
                           otherwise required by the Act; and (ii) in the event
                           of any liquidation, dissolution or winding-up of the
                           Corporation, whether voluntary or involuntary,
                           holders of each share of Common Stock Series C,
                           Common Stock Series B and Common Stock Series E shall
                           be entitled to be paid first out of the assets of the
                           Corporation available for distribution to holders of
                           the Corporation's capital stock of all classes or
                           series, before any sums shall be paid or any assets
                           distributed among the holders of shares of Common
                           Stock, Common Stock Series D or Common Stock Series
                           F, in an amount equal to $1.00 per share of Common
                           Stock Series C.

                                    The Corporation is authorized to issue
                           15,000,000 shares of Common Stock Series D, without
                           par value per share. The Common Stock Series D shall
                           have rights that are identical to that of the Common
                           Stock, except that shares of Common Stock Series D
                           shall have no voting rights except as may be
                           otherwise required by the Act.

                                    The Corporation is authorized to issue
                           2,500,000 shares of Common Stock Series E, without
                           par value per share. The Common Stock Series E shall
                           have rights that are identical to that of the Common
                           Stock, except that (i) shares of Common Stock Series
                           E shall have no voting rights except as may be
                           otherwise required by the Act; and (ii) in the event
                           of any liquidation, dissolution or winding-up of the
                           Corporation, whether voluntary or involuntary,
                           holders of each share of Common Stock Series E,
                           Common Stock Series C and Common Stock Series B shall
                           be entitled to be paid first out of the assets of the
                           Corporation available for distribution to holders of
                           the Corporation's capital stock of all classes or
                           series, before any sums shall be paid or any assets
                           distributed among the holders of shares of Common
                           Stock, Common Stock Series D or Common Stock Series
                           F, in an amount equal to $1.00 per share of Common
                           Stock Series E.

                                     2.4-2


>PAGE>   50


                                    The Corporation is authorized to issue
                           5,000,000 shares of Common Stock Series F, without
                           par value per share. The Common Stock Series F shall
                           have rights that are identical to that of the Common
                           Stock, except that shares of Common Stock Series F
                           shall have no voting rights except as may be
                           otherwise required by the Act.

                                    If the assets of the Corporation are
                           insufficient to permit the payment in full to the
                           holders of the Common Stock Series B, Series C and
                           Series E of the amounts distributable to such holders
                           upon the liquidation, dissolution or winding-up of
                           the Corporation, then the assets of the Corporation
                           available for such distribution shall be distributed
                           ratably among the holders of the Common Stock Series
                           B, Common Stock Series C and Common Stock Series E
                           based on the relative liquidation preferences of the
                           Common Stock Series B, Common Stock Series C and
                           Common Stock Series E. For purposes of effecting such
                           ratable distribution between the Common Stock Series
                           B, Common Stock Series C and Common Stock Series E,
                           each share of Common Stock Series B will be entitled
                           to $0.285714 per each $1.00 to be distributed to each
                           share of Common Stock Series C or Common Stock Series
                           E.

                                    Whenever a distribution provided for herein
                           shall be paid in property other than cash, the value
                           of such property shall be its fair market value as
                           determined in good faith by the Board of Directors of
                           the Corporation.

                                    Holders of Common Stock, whether with or
                           without designation as to series, shall be entitled
                           to receive such dividends and other distributions in
                           cash, stock or property of the Corporation as may be
                           declared by the Board of Directors from time to time
                           out of funds of the Corporation legally available
                           therefor.

                                    Immediately prior to the closing of an
                           Initial Public Offering, each issued and outstanding
                           share of Common Stock Series B, Common Stock Series
                           C, Common Stock Series D, Common Stock Series E and
                           Common Stock Series F will become and be, without
                           further act by the holders of any Common Stock of the
                           Corporation, whether with or without designation as
                           to series, automatically converted into one share of
                           Common Stock, without designation as to series, and
                           the Board of Directors of the Corporation may
                           thereafter at its election file Articles of Amendment
                           to the Articles of Incorporation without further vote
                           or action by the holders of any Common Stock of the
                           Corporation, whether with or without designation as
                           to series, confirming the elimination of the series
                           designations of Common Stock, which amendment shall
                           amend and restate the first sentence of Article II of
                           the Corporation's Amended and Restated Articles of
                           Incorporation to read in full as follows:


                                     2.4-3
>PAGE>   51


                                            "The total number of shares of stock
                                    of all classes which the Corporation has the
                                    authority to issue is 85,000,000, of which
                                    75,000,000 shares are designated as Common
                                    Stock and of which 10,000,000 shares are
                                    designated as Preferred Stock."

                           and shall amend and restate Section A of Article II
                           of the Corporation's Articles of Incorporation to
                           read in full as follows:

                                             "The Corporation is authorized to
                                    issue 75,000,000 shares of Common Stock
                                    without par value per share. Each share of
                                    Common Stock shall be entitled to one
                                    vote."

                                    The term "Initial Public Offering" means the
                           offer and sale by the Corporation of its equity
                           securities in a transaction underwritten by an
                           investment banking firm following the completion of
                           which (i) such equity securities will be listed for
                           trading on any national securities exchange or (ii)
                           there will be at least two market makers who are
                           making a market in such equity securities through the
                           Nasdaq National Market System."

         4.       In accordance with Section 14-2-1003 of the Georgia Business
                  Corporation Code, the amendment contained herein was duly
                  adopted at a meeting of the Board of Directors held on August
                  ___, 1998 and submitted to a vote of the shareholders entitled
                  to vote thereon. Such shareholders duly adopted the amendment
                  contained herein at a meeting held on August ___, 1999.


                      [SIGNATURES FOLLOW ON THE NEXT PAGE]



                                     2.4-4

>PAGE>   52


         IN WITNESS WHEREOF, the Corporation has caused these Articles of
Amendment to be signed by the undersigned duly authorized officer, this _____
day of __________, 1999.

                                               WEBMD, INC.


                                               By:
                                                  -----------------------------

                                               Name (print):
                                                            -------------------

                                               Title:
                                                     --------------------------



                                     2.4-5
>PAGE>   53


                                  EXHIBIT 3.1


                            FORM OF VOTING AGREEMENT



                                VOTING AGREEMENT


         This Voting Agreement (this "AGREEMENT") is made and entered into as of
________, 1999, by and between Healtheon Corporation, a Delaware corporation
("HEALTHEON"), and HBO & Company, a Delaware corporation (the "SHAREHOLDER"), a
shareholder of WebMD, Inc., a Georgia corporation (the "COMPANY").

                                    RECITALS

         A.       Healtheon, the Company and Water Acquisition Corp., a wholly
owned subsidiary of Healtheon ("MERGER SUB"), entered into an Agreement and
Plan of Reorganization dated as of May 20, 1999 (as the same may be amended
from time to time, the "MERGER AGREEMENT"), which provides for the combination
of the businesses of Healtheon and the Company. The Merger Agreement provides
for such combination to be effected through one of two structures; a subsidiary
of Healtheon/WebMD Corporation, a newly formed Delaware corporation
("HEALTHEON/WEBMD") may be merged with and into Healtheon and another
subsidiary of Healtheon/WebMD merged into the Company ("REORGANIZATION
STRUCTURE ONE") or Merger Subsidiary may be merged with and into the Company
("REORGANIZATION STRUCTURE TWO"). The merger of a subsidiary of Healtheon/WebMD
into the Company (in the event the combination is effected through
Reorganization Structure One) or the merger of Merger Sub into the Company (in
the event the combination is effected through Reorganization Structure Two) is
referred to herein as the "MERGER."

         B.       Shareholder is the record holder of 967,000 shares of Series
A Preferred Stock of the Company and 650,000 shares of Series B Preferred Stock
of the Company.

         C.       In consideration of one dollar ($1.00) and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the Shareholder is willing to agree to vote the Shares (as
defined below) and the New Shares (as defined below) so as to facilitate
consummation of the Merger.

         NOW, THEREFORE, intending to be legally bound, the parties agree as
follows:

         1.       AGREEMENT TO VOTE SHARES; ADDITIONAL PURCHASES; TRANSFERS AND
ENCUMBRANCE.

         1.1      AGREEMENT TO VOTE SHARES. At every meeting of the
shareholders of the Company called with respect to any of the following, and at
every adjournment thereof, and on every action or approval by written consent
of the shareholders or any group of shareholders of the Company with respect to
any of the following, Shareholder shall cause the Shares and any New Shares (as
defined below) to be voted:

>PAGE>   54

                  (i)   in favor of the adoption of the amendment to the
Designations of the Preferences, Limitations and Relative Rights of the Series A
Preferred Stock of the Company and the amendment to the Designations of the
Preferences, Limitations and Relative Rights of the Series B Preferred Stock of
the Company, each as set forth on Exhibit A hereto;

                  (ii)  in favor of approval of the Merger and the adoption and
approval of the Merger Agreement, including all actions contemplated thereby;

                  (iii) in favor of the conversion of all shares of preferred
stock of the Company into shares of Common Stock immediately prior to, and
contingent upon, the Closing of the Merger;

                  (iv)  in favor of approval of any payments, purchases, sales
or accelerations of capital stock of the executive officers of the Company that
may be deemed to constitute "parachute payments" pursuant to Section 280G of
the Internal Revenue Code of 1986, as amended;

                  (v)   against approval of any proposal made in opposition to,
or in competition with, consummation of the Merger and the Merger Agreement;
and

                  (vi)  against any of the following actions (other than those
actions that relate to the Merger and are contemplated by the Merger
Agreement): (A) any merger, consolidation, business combination, sale of
assets, reorganization or recapitalization of the Company with any party; (B)
any dissolution, liquidation or winding up of the Company; (C) any joint
venture or material strategic relationship with any party; (D) any material
change in the capitalization of the Company or the Company's capital structure,
except as contemplated by this Section 1.1 and Section 3 hereof or the Merger
Agreement or any other voting agreement or conversion agreement entered into in
connection therewith; or (E) any other action that is intended, or could
reasonably be expected to impede, interfere with, delay, postpone, discourage
or adversely affect the Merger or any of the transactions contemplated by the
Merger Agreement.

                  Notwithstanding the foregoing or any other provision contained
in this Agreement, Shareholder shall not be obligated to vote in favor of the
Merger and the adoption and approval of the Merger Agreement in the event the
Exchange Ratio (as defined in the Merger Agreement) is reduced below 1.796.

         1.2      DEFINITION. For purposes of this Agreement, "SHARES" shall
mean all issued and outstanding shares of capital stock of the Company for
which Shareholder is the beneficial owner or over which Shareholder has voting
control, including any securities convertible into, or exercisable or
exchangeable for shares of the Company's capital stock, all as set forth in the
Recitals hereto.

         1.3      ADDITIONAL PURCHASES. Shareholder agrees that any shares of
capital stock of the Company that Shareholder purchases or with respect to
which Shareholder otherwise acquires beneficial ownership or voting control
after the execution of this Agreement and prior to the date of termination of
this Agreement ("NEW Shares") shall be subject to the terms and conditions of
this Agreement to the same extent as if they constituted Shares.

         1.4      TRANSFER AND ENCUMBRANCE. Prior to the Merger, Shareholder
agrees not to transfer, sell, exchange, pledge, gift, or otherwise dispose of
or encumber (collectively, "TRANSFER") any of the

                                     3.1-2
>PAGE>   55


Shares or any New Shares or to discuss, negotiate, or make any offer or
agreement relating thereto, other than to or with Healtheon or WebMD without
the prior written consent of Healtheon, which consent shall not be withheld to
the extent that such Transfer does not result in less than a majority of the
outstanding shares of any class or series of capital stock of WebMD (computed
assuming exercise of all outstanding options and warrants) being subject to
provisions of this Agreement or a voting agreement substantially similar to
this Agreement; provided that no person who is not an affiliate of WebMD as
that term is used in Rule 145 of the Securities Act shall execute a voting
agreement. Shareholder acknowledges that the intent of the foregoing sentence
is to ensure that Healtheon retains the right under the Proxy (as defined in
Section 2 hereof) to vote a sufficient number of the Shares and any New Shares
in accordance with the terms of the Proxy to ensure the approval of the
transactions contemplated by the Merger Agreement.

         2.       IRREVOCABLE PROXY. Concurrently with the execution of this
Agreement, Shareholder agrees to deliver to Healtheon a proxy in the form
attached hereto as Exhibit B (the "PROXY") with respect to the Shares and New
Shares, which, subject to Section 7 hereof, shall be irrevocable to the fullest
extent permitted by applicable law.

         3.       ELECTION TO CONVERT PREFERRED STOCK INTO COMMON STOCK.
Effective immediately prior to the Effective Time (as defined in the Merger
Agreement) of the Merger, Shareholder hereby irrevocably elects to convert all
shares of all series of preferred stock of the Company held by Shareholder into
shares of Common Stock of the Company in accordance with the Company's Articles
of Incorporation, as amended through the consummation of the Merger.

         4.       REPRESENTATIONS AND WARRANTIES OF THE SHAREHOLDER.

                  (i)   With respect to the Shares owned by Shareholder,
Shareholder is the owner of the Shares free and clear of any liens, claims,
options, charges or other encumbrances.

                  (ii)  Shareholder (A) has full authority to vote and direct
the voting of the Shares; (B) does not beneficially own any securities of the
Company other than the Shares indicated on the final page of this Agreement;
and (C) has full power and authority to make, enter into and carry out the
terms of this Agreement and the Proxy.

                  (iii) Shareholder has been advised that (A) the issuance of
shares of Healtheon/WebMD Common Stock (in the event the business combination is
effected through Reorganization Structure One) or Healtheon Common Stock (in the
event the combination is effected through Reorganization Structure Two) in
connection with the Merger is expected to be effected pursuant to a Registration
Statement on Form S-4 under the Securities Act of 1933, as amended (the "ACT"),
and as such will not be deemed "restricted securities" within the meaning of
Rule 144 promulgated thereunder and resale thereof shall be subject to the
restrictions set forth in Rule 145 of the Act and (B) Shareholder may be deemed
to be an affiliate of the Company, Healtheon and/or Healtheon/WebMD. Shareholder
accordingly agrees not to sell, transfer or otherwise dispose of any
Healtheon/WebMD Common Stock or Healtheon Common Stock issued to Shareholder in
the Merger unless (x) such sale, transfer or other disposition is made in
conformity with the requirements of Rule 145(d) promulgated under the Act and in
effect on the date of such sale, transfer or other disposition, (y) an
authorized representative of the SEC takes the position in writing to the effect
that the SEC would take no action, or that the staff of the SEC would not
recommend that the SEC take action, with respect to such sale, transfer or other
disposition, and a copy of such written position ("NO ACTION


                                     3.1-3
>PAGE>   56

CORRESPONDENCE") is delivered to Healtheon/WebMD or Healtheon, as the case may
be, or (z) Shareholder delivers to Healtheon/WebMD or Healtheon, as the case
may be, a written opinion of counsel, reasonably acceptable to Healtheon/WebMD
or Healtheon, as the case may be, in form and substance, that such sale,
transfer or other disposition is otherwise exempt from registration under the
Act.

                  (iv) Healtheon/WebMD or Healtheon, as the case may be, will
give stop transfer instructions to its transfer agent with respect to any
Healtheon/WebMD Common Stock or Healtheon Common Stock received by Shareholder
pursuant to the Merger and there will be placed on the certificates representing
such Healtheon/WebMD Common Stock or Healtheon, as the case may be, or any
substitutions therefor, a legend stating in substance:

         "THE SHARES REPRESENTED BY THIS CERTIFICATE WERE ISSUED IN A
         TRANSACTION TO WHICH RULE 145 PROMULGATED UNDER THE SECURITIES ACT OF
         1933, AS AMENDED, APPLIES AND MAY ONLY BE TRANSFERRED (A) IN CONFORMITY
         WITH RULE 145(d) UNDER SUCH ACT, OR (B) IN ACCORDANCE WITH A WRITTEN
         OPINION OF COUNSEL, REASONABLY ACCEPTABLE TO THE ISSUER IN FORM AND
         SUBSTANCE THAT SUCH TRANSFER IS EXEMPT FROM REGISTRATION UNDER THE
         SECURITIES ACT OF 1933, AS AMENDED."

The legend set forth above shall be removed (by delivery of a substitute
certificate without such legend) and Healtheon/WebMD or Healtheon, as the case
may be, shall instruct its transfer agent to remove such legend, if Shareholder
delivers to Healtheon/WebMD or Healtheon, as the case may be, (A) satisfactory
written evidence that the shares have been sold in compliance with Rule 145 (in
which case, the substitute certificate will be issued in the name of the
transferee), (B) a copy of the No Action Correspondence, (C) an opinion of
counsel, in form and substance reasonably satisfactory to Healtheon/WebMD or
Healtheon, as the case may be, to the effect that public sale of the shares by
the holder thereof is no longer subject to Rule 145, or (D) a written request
for removal of such legend after the earlier of (x) the inapplicability of Rule
145 by its terms, or (y) the effective date of any action by the SEC eliminating
the restrictions upon sale, transfer or disposition under Rule 145 or otherwise
rendering compliance with such restrictions unnecessary.


         5.       ADDITIONAL DOCUMENTS; SHAREHOLDER AGREEMENT. Shareholder and
Healtheon hereby covenant and agree to execute and deliver any additional
documents necessary or desirable, in the reasonable opinion of Healtheon or
Shareholder, as the case may be, to carry out the intent of this Agreement.
Shareholder agrees to take such action as may be required by it to terminate
the Restated Stockholders Agreement dated October 18, 1996, as amended, and the
Shareholders Agreement dated August 24, 1998, as amended, effective as of the
consummation of the Merger.

         6.       CONSENT AND WAIVER. Shareholder hereby gives any consents or
waivers that may otherwise be required for the consummation of the Merger under
the terms of any agreements to which Shareholder is a party or pursuant to any
rights Shareholder may have.

         7.       TERMINATION. This Agreement and the Proxy shall terminate and
shall have no further force or effect as of the earlier to occur of (i) such
date and time as the Merger shall become effective in accordance with the terms
and provisions of the Merger Agreement (in which case the


                                     3.1-4

>PAGE>   57

provisions of Section 4 (iii) and (iv) above shall continue to apply) or (ii)
such date and time as the Merger Agreement shall have been terminated in
accordance with its terms.

         8.       MISCELLANEOUS.

         8.1      FIDUCIARY OBLIGATIONS. Nothing in this Agreement shall be
interpreted to limit the discharge of any fiduciary obligations of a director
who is a designee of the Shareholder serving on the Board of Directors of the
Company, solely in such designee's capacity as a director of the Company and
not in the Shareholder's capacity as owner of its Shares.

         8.2      SEVERABILITY. If any term, provision, covenant or restriction
of this Agreement is held by a court of competent jurisdiction to be invalid,
void or unenforceable, then the remainder of the terms, provisions, covenants
and restrictions of this Agreement shall remain in full force and effect and
shall in no way be affected, impaired or invalidated.

         8.3      BINDING EFFECT AND ASSIGNMENT. This Agreement and all of the
provisions hereof shall be binding upon and inure to the benefit of the parties
hereto and their respective successors and permitted assigns and any person or
entity to which legal or beneficial ownership of such Shares or New Shares
shall pass whether by operation of law or otherwise, but, except as otherwise
specifically provided herein, neither this Agreement nor any of the rights,
interests or obligations of the parties hereto may be assigned by either of the
parties without prior written consent of the other.

         8.4      AMENDMENTS AND MODIFICATION. This Agreement may not be
modified, amended, altered or supplemented except upon the execution and
delivery of a written agreement executed by the parties hereto.

         8.5      SPECIFIC PERFORMANCE; INJUNCTIVE RELIEF. The parties hereto
acknowledge that Healtheon will be irreparably harmed and that there will be no
adequate remedy at law for a violation of any of the covenants or agreements of
Shareholder set forth herein. Therefore, it is agreed that, in addition to any
other remedies that may be available to Healtheon upon any such violation,
Healtheon shall have the right to enforce such covenants and agreements by
specific performance, injunctive relief or by any other means available to
Healtheon at law or in equity.

         8.6      NOTICES. All notices, requests, claims, demands and other
communications hereunder shall be in writing and sufficient if delivered in
person or sent by overnight courier by a reputable carrier (prepaid) to the
respective parties as follows:

         If to WebMD                        Healtheon Corporation
           or Healtheon:                    4600 Patrick Henry Drive
                                            Santa Clara, California 95054
                                            Attention: Jack Dennison, Esq.

                                                     and

                                            WebMD, Inc.
                                            400 The Lenox Building
                                            3399 Peachtree Road
                                            Atlanta, Georgia 30326


                                     3.1-5
>PAGE>   58



                                      Attention:  W. Michael Heekin. Esq.

         With copies to:              Nelson Mullins Riley & Scarborough, L.L.P.
                                      Bank of America Corporate Center
                                      Suite 2600
                                      100 North Tryon Street
                                      Charlotte, North Carolina 28202
                                      Attention: H. Bryan Ives III, Esq.
                                                 C. Mark Kelly, Esq.

                                               and

                                      Wilson Sonsini Goodrich & Rosati, P.C.
                                      650 Page Mill Road
                                      Palo Alto, California 94304-1050
                                      Attention: Larry W. Sonsini, Esq.
                                                 Martin W. Korman, Esq.
                                                 Daniel R. Mitz, Esq.

         If to Shareholder:           McKesson HBOC, Inc.
                                      One Post Street
                                      San Francisco, California 94104
                                      Attention: General Counsel

         With a copy to:              Jones, Day, Reavis & Pogue
                                      3500 SunTrust Plaza
                                      303 Peachtree Street
                                      Atlanta, Georgia 30308-3242
                                      Attention: Robert W. Smith, Esq.

                                               and

                                      Skadden, Arps, Slate, Meagher & Flom LLP
                                      525 University Avenue, Suite 220
                                      Palo Alto, CA 94301
                                      Attention: Kenton J. King, Esq.

or to such other address as any party may have furnished to the other in writing
in accordance herewith, except that notices of change of address shall only be
effective upon receipt.

         8.7      GOVERNING LAW. This Agreement shall be governed by, and
construed and enforced in accordance with, the internal laws of the State of
Georgia (without regard to the principles of conflict of laws thereof).

         8.8      ENTIRE AGREEMENT. This Agreement contains the entire
understanding of the parties in respect of the subject matter hereof, and
supersedes all prior negotiations and understandings between the parties with
respect to such subject matter.


                                     3.1-6
>PAGE>   59


         8.9      COUNTERPARTS. This Agreement may be executed in several
counterparts, each of which shall be an original, but all of which together
shall constitute one and the same agreement.

         8.10     EFFECT OF HEADINGS. The section headings herein are for
convenience only and shall not affect the construction or interpretation of
this Agreement.



                      [SIGNATURES FOLLOW ON THE NEXT PAGE]



                                     3.1-7

>PAGE>   60


         IN WITNESS WHEREOF, the parties have caused this Voting Agreement to be
duly executed on the date and year first above written.

                                   WEBMD, INC.


                                   By:
                                      -----------------------------------------
                                      Its:



                                   HEALTHEON CORPORATION


                                   By:
                                      -----------------------------------------
                                      Its:



                                   HBO & COMPANY


                                   By:
                                      ------------------------------------------
                                      Its:


                                     3.1-8


>PAGE>   61


                                    EXHIBIT A

                                  AMENDMENT TO
                          CERTIFICATES OF DESIGNATIONS

AMENDMENT TO CERTIFICATE OF DESIGNATIONS OF SERIES A PREFERRED STOCK

         "RESOLVED, that the term "Common Stock" used in Subsection (d)(3)(A) in
the Designations of Preferences, Limitations and Relative Rights of the Series A
Preferred Stock of WebMD, Inc. contained in Article II.B of the Amended and
Restated Articles of Incorporation is hereby amended to mean, for purposes of
Subsection (d)(3)(A) only, the Common Stock Series D, no par value per share, of
the Corporation."


AMENDMENT TO CERTIFICATE OF DESIGNATIONS OF SERIES B PREFERRED STOCK

         "RESOLVED, that the term "Common Stock" used in Subsection (d)(3)(A) in
the Designations of Preferences, Limitations and Relative Rights of the Series B
Preferred Stock of WebMD, Inc. contained in Article II.B of the Amended and
Restated Articles of Incorporation is hereby amended to mean, for purposes of
Subsection (d)(3)(A) only, the Common Stock Series D, no par value per share, of
the Corporation."


                                     3.1-9


>PAGE>   62


                                    EXHIBIT B

                                IRREVOCABLE PROXY


         The undersigned Shareholder of WebMD, Inc., a Georgia corporation (the
"COMPANY"), hereby irrevocably appoints the directors on the Board of Directors
of Healtheon Corporation, a Delaware corporation ("HEALTHEON"), and each of
them, as the sole and exclusive attorneys and proxies of the undersigned, with
full power of substitution and resubstitution, to the full extent of the
undersigned's rights with respect to the voting of the Shares and New Shares (as
each such term is defined in the Voting Agreement of even date between Healtheon
and the Shareholder (the "VOTING AGREEMENT")) on the matters described below
(and on no other matter), until such time as that certain Agreement and Plan of
Reorganization dated as of May 20, 1999 among Healtheon, Water Acquisition
Corp., a Georgia corporation ("MERGER SUB"), and the Company (the Agreement and
Plan of Reorganization, as the same may be amended from time to time, is
referred to herein as the "MERGER AGREEMENT"), shall be terminated in accordance
with its terms or the Merger (as defined in the Merger Agreement) becomes
effective. Upon the execution hereof, all prior proxies given by the undersigned
with respect to the Shares and any and all other shares or securities issued or
issuable in respect thereof on or after the date hereof are hereby revoked and
no subsequent proxies will be given.

         This proxy is irrevocable (to the fullest extent permitted by law and
subject to the termination of the Proxy as set forth in Section 7 of the Voting
Agreement), is granted pursuant to the Voting Agreement, is granted in
consideration of Healtheon entering into the Merger Agreement and is coupled
with an interest. The attorneys and proxies named above will be empowered at any
time prior to the earlier of termination of the Merger Agreement and the date on
which the Merger becomes effective to exercise all voting rights (including,
without limitation, the power to execute and deliver written consents with
respect to the Shares and the New Shares) of the undersigned at every annual,
special or adjourned meeting of the Company's shareholders, and in every written
consent in lieu of such a meeting, or otherwise, to vote the Shares and the New
Shares:

                  (i)   in favor of the adoption of the amendment to the
Designations of the Preferences, Limitations and Relative Rights of the Series A
Preferred Stock of the Company and the amendment to the Designations of the
Preferences, Limitations and Relative Rights of the Series B Preferred Stock of
the Company, each as set forth on Exhibit A hereto;

                  (ii)  in favor of approval of the Merger and the adoption and
approval of the Merger Agreement, including all actions contemplated thereby;

                  (iii) in favor of the conversion of all shares of preferred
stock of the Company into shares of Common Stock immediately prior to, and
contingent upon, the Closing of the Merger;

                  (iv)  in favor of approval of any payments, purchases, sales
or accelerations of capital stock of the executive officers of the Company that
may be deemed to constitute "parachute payments" pursuant to Section 280G of
the Internal Revenue Code of 1986, as amended.

                  (v)   against approval of any proposal made in opposition to,
or in competition with, consummation of the Merger and the Merger Agreement;
and


                                    3.1-10


>PAGE>   63

                  (vi) against any of the following actions (other than those
actions that relate to the Merger and are contemplated by the Merger Agreement):
(A) any merger, consolidation, business combination, sale of assets,
reorganization or recapitalization of the Company with any party; (B) any
dissolution, liquidation or winding up of the Company; (C) any joint venture or
material strategic relationship with any party; (D) any material change in the
capitalization of the Company or the Company's capital structure, except as
contemplated by the Merger Agreement and by Section 1.2(ii) and Section 3 of the
Voting Agreement; or (E) any other action that is intended, or could reasonably
be expected to impede, interfere with, delay, postpone, discourage or adversely
affect the Merger or any of the transactions contemplated by the Merger
Agreement.

         The attorneys and proxies named above may only exercise this proxy to
vote the Shares and any New Shares subject hereto at any time prior to the
earlier of termination of the Merger Agreement and the date on which the Merger
becomes effective, at every annual, special or adjourned meeting of the
shareholders of the Company and in every written consent in lieu of such
meeting. The undersigned Shareholder may vote the Shares and New Shares on all
other matters.

         Any obligation of the undersigned hereunder shall be binding upon the
successors and assigns of the undersigned.

         This proxy is irrevocable and coupled with an interest.

Dated:   ____________, 1999


                                  HBO & COMPANY


                                  By:
                                     ----------------------------------
                                  Its:


                                    3.1-11



>PAGE>   64


                                    EXHIBIT A
                                       TO
                                IRREVOCABLE PROXY


                                  AMENDMENT TO
                          CERTIFICATES OF DESIGNATIONS

AMENDMENT TO CERTIFICATE OF DESIGNATIONS OF SERIES A PREFERRED STOCK

         "RESOLVED, that the term "Common Stock" used in Subsection (d)(3)(A) in
the Designations of Preferences, Limitations and Relative Rights of the Series A
Preferred Stock of WebMD, Inc. contained in Article II.B of the Amended and
Restated Articles of Incorporation is hereby amended to mean, for purposes of
Subsection (d)(3)(A) only, the Common Stock Series D, no par value per share, of
the Corporation."


AMENDMENT TO CERTIFICATE OF DESIGNATIONS OF SERIES B PREFERRED STOCK

         "RESOLVED, that the term "Common Stock" used in Subsection (d)(3)(A) in
the Designations of Preferences, Limitations and Relative Rights of the Series B
Preferred Stock of WebMD, Inc. contained in Article II.B of the Amended and
Restated Articles of Incorporation is hereby amended to mean, for purposes of
Subsection (d)(3)(A) only, the Common Stock Series D, no par value per share, of
the Corporation."




                                    3.1-12




>PAGE>   65
                                 EXHIBIT 4.1(A)


                            CAPITALIZATION OF WEBMD

         As of August 30, 1999, the authorized and issued capital stock of WebMD
consisted of (a) 75,000,000 shares designated common stock (without designation
as to series), of which 2,455,334 shares were issued and outstanding and none of
which were issued and held as treasury shares, (b) 3,000,000 shares designated
common stock Series B, of which 1,400,000 were issued and outstanding and none
of which were issued and held as treasury shares, (c) 1,500,000 shares
designated common stock Series C, of which 1,500,000 were issued and outstanding
and none of which were issued and held as treasury shares, (d) 15,000,000 shares
designated common stock Series D, of which 5,939,883 were issued and outstanding
and none of which were issued and held as treasury shares, (e) 2,500,000 shares
designated common stock Series E, of which 2,100,000 were issued and outstanding
and none of which were issued and held as treasury shares; and (f) 10,000,000
shares designated as preferred stock, of which (i) 1,600,000 shares were
designated Series A preferred stock, of which 1,341,000 are issued and
outstanding and none of which were issued and held as treasury shares, (ii)
3,400,000 shares were designated Series B preferred stock, of which 3,047,204
were issued and outstanding and none of which were issued and held as treasury
shares, (iii) 2,000,000 shares were designated Series C preferred stock, of
which 1,008,750 were issued and outstanding and none of which were issued and
held as treasury shares, (iv) 200,000 shares were designated Series D preferred
stock, of which 200,000 were issued and outstanding and none of which were
issued and held as treasury shares, (v) 792,000 shares were designated Series E
preferred stock, of which 456,896 were issued and outstanding and none of which
were issued and held as treasury shares, and (vi) 1,180,000 shares were
designated Series F preferred stock, of which 814,339 were issued and
outstanding and none of which were issued and held as treasury shares. WebMD has
no other capital stock authorized, issued or outstanding. All of such shares are
duly and validly issued and outstanding, and are fully paid and non-assessable.
As of August 30, 1999, there are outstanding options and warrants to purchase
capital stock of WebMD, which in the aggregate on a fully vested, exercised and
converted basis represent rights to acquire 23,211,888 shares of common stock of
WebMD, exclusive of the right and obligation of Microsoft Corporation to
purchase 276,906 shares of Series E preferred stock prior to and conditioned
upon on the Healtheon-WebMD Closing. Since August 30, 1999, WebMD has not issued
any capital stock except in connection with the exercise of options and
warrants.


                                      4.1