EXECUTION COPY

                       FIRST AMENDMENT TO CREDIT AGREEMENT

     FIRST AMENDMENT TO CREDIT AGREEMENT (this "First  Amendment"),  dated as of
February 11, 2004, among WYETH, a Delaware corporation (the "Company"),  various
lenders from time to time party to the Credit  Agreement  referred to below (the
"Lenders"),  and JPMORGAN CHASE BANK, as Administrative Agent (in such capacity,
the "Administrative  Agent"). Unless otherwise indicated,  all capitalized terms
used  herein  and not  otherwise  defined  shall  have the  respective  meanings
provided such terms in the Credit Agreement referred to below.

                              W I T N E S S E T H :

     WHEREAS,  the  Company,  the  Lenders,  J.P.  Morgan  Securities  Inc.  and
Citigroup  Global  Markets Inc.  (f/k/a  Salomon Smith Barney Inc.),  as Co-Lead
Arrangers and Joint Book Managers,  Citibank,  N.A., as Syndication  Agent,  The
Bank of Nova Scotia, Commerzbank AG, New York and Grand Cayman Branches, and UBS
AG, Cayman Islands Branch, as Co- Documentation  Agents,  and the Administrative
Agent are parties to a Credit Agreement,  dated as of March 3, 2003 (the "Credit
Agreement"); and

     WHEREAS,  subject to the terms and conditions of this First Amendment,  the
parties hereto wish to amend the Credit Agreement as herein provided;

NOW, THEREFORE, it is agreed:

I.       Amendments to Credit Agreement.

     1. Subsection 1.1 of the Credit Agreement is hereby amended by deleting the
text  "364-Day  Credit  Agreement"  appearing  in  each  of the  definitions  of
"Aggregate Facilities Commitment" and "Significant Usage Period" in said Section
and inserting the text "5-Year Credit Agreement" in lieu thereof.

     2. The definition of "Applicable Margin" appearing in subsection 1.1 of the
Credit  Agreement  is hereby  amended by deleting  the table  appearing  in said
definition and inserting the following table in lieu thereof:

                                                       Eurodollar
                     "Rating                             Rate
                      Period                             Margin
         ------------------------------------ --------------------------------
         ------------------------------------ --------------------------------

                Category A Period                       .3750%
                Category B Period                       .600%
                Category C Period                       .825%
                Category D Period                       1.050%
                Category E Period                       1.275%
                Category F Period                       1.500%".

     3. The definition of "Category E Period" appearing in subsection 1.1 of the
Credit  Agreement  is hereby  amended  by  deleting  the text "or lower" in each
instance where it appears in said definition.

     4. The  definition of "Category  Rules"  appearing in subsection 1.1 of the
Credit  Agreement is hereby  amended by deleting  each  reference to "Category E
Period"  appearing in said definition and inserting the text "Category F Period"
in lieu thereof.

     5. The definition of "Facility Fee Percentage"  appearing in subsection 1.1
of the  Credit  Agreement  is hereby  amended  by (i)  deleting  the word  "and"
appearing at the end of clause (iv) of said  definition and inserting a comma in
lieu thereof and (ii)  inserting  the text "and (vi) during a Category F Period,
0.250%" immediately preceding the period at the end of said definition.

     6. The  definition of "Rating  Period"  appearing in subsection  1.1 of the
Credit  Agreement is hereby amended by (i) changing the reference to "Category E
Period"  appearing in said  definition to "Category F Period" and (ii) inserting
the text ", the Category E Period"  immediately  following the text  "Category D
Period" appearing in said definition.

     7.  Subsection  1.1 of the Credit  Agreement is hereby  further  amended by
inserting the following definitions in the appropriate alphabetical order:

          "Category F Period": subject to the Category Rules, at any time either
     (i) the S&P Credit Rating is BB+ or lower or (ii) the Moody's Credit Rating
     is Ba1 or lower.

          "5-Year Credit Agreement":  the Credit Agreement, dated as of February
     11,  2004,  among  the  Company,  the  lenders  party  thereto,  JPMCB,  as
     administrative  agent,  and Citicorp  North  America,  Inc., as syndication
     agent, as in effect from time to time.

     8.  Subsection  2.18 of the Credit  Agreement is hereby amended by deleting
each reference to "364-Day Credit Agreement" appearing therein and inserting the
text "5-Year Credit Agreement" in lieu thereof.

     9. Subsection 8.14(a) of the Credit Agreement is hereby amended by deleting
said  subsection  in its entirety  and  inserting  the text "(a)  [Intentionally
deleted]" in lieu thereof.

II.      Miscellaneous Provisions.

     1. In order to induce the Lenders to enter into this First  Amendment,  the
Company  hereby  represents and warrants that (i) no Default or Event of Default
exists as of the Amendment  Effective  Date, both before and after giving effect
to this  First  Amendment  and (ii) all of the  representations  and  warranties
contained in the Credit Agreement are true and correct in all material  respects
on the  Amendment  Effective  Date,  both before and after giving effect to this
First  Amendment,  with the same  effect  as  though  such  representations  and
warranties  had been made on and as of the  Amendment  Effective  Date (it being
understood that any  representation or warranty made as of a specific date shall
be true and correct in all material respects as of such specific date).

     2. This First  Amendment is limited as specified and shall not constitute a
modification,  acceptance  or  waiver  of any  other  provision  of  the  Credit
Agreement.

     3. This First Amendment may be executed in any number of  counterparts  and
by the  different  parties  hereto  on  separate  counterparts,  each  of  which
counterparts when executed and delivered shall be an original,  but all of which
shall  together  constitute  one and the  same  instrument.  A  complete  set of
counterparts shall be lodged with the Company and the Administrative Agent.

     4. THIS  FIRST  AMENDMENT  AND THE RIGHTS AND  OBLIGATIONS  OF THE  PARTIES
HEREUNDER  SHALL BE CONSTRUED IN ACCORDANCE  WITH AND GOVERNED BY THE LAW OF THE
STATE OF NEW YORK.

     5. This First Amendment shall become  effective on the date (the "Amendment
Effective  Date") when (i) the Company and  Lenders  constituting  the  Majority
Lenders  shall have signed a counterpart  hereof  (whether the same or different
counterparts)   and  shall  have  delivered   (including  by  way  of  facsimile
transmission)  the same to White & Case LLP,  1155 Avenue of the  Americas,  New
York, NY 10036 Attention:  May Yip (facsimile number  212-354-8113) and (ii) the
5-Year  Credit  Agreement  shall have become  effective in  accordance  with its
terms.

     6. From and after the  Amendment  Effective  Date,  all  references  in the
Credit  Agreement  shall be deemed to be references  to the Credit  Agreement as
modified hereby.

                                 * * *

     IN WITNESS  WHEREOF,  the parties hereto have caused their duly  authorized
officers to execute  and deliver  this  Amendment  as of the date first  written
above.




                                       WYETH


                                       By:  /s/ Kenneth J. Martin
                                          -------------------------------------
                                          Title: Executive Vice President and
                                                 Chief Financial Officer



                                       JPMORGAN CHASE BANK,
                                          Individually and as Administrative
                                          Agent


                                       By: /s/ Robert Anastasio
                                          -------------------------------------
                                          Title: Vice President



                                       CITIBANK N.A.,
                                          Individually and as Syndication
                                          Agent

                                       By: /s/ Wajeeh Faheen
                                          -------------------------------------
                                          Title: Vice President



                                       THE BANK OF NOVA SCOTIA

                                       By: /s/ Carolyn A. Calloway
                                          -------------------------------------
                                          Title: Managing Director



                                       COMMERZBANK AG, NEW YORK AND GRAND
                                          CAYMAN BRANCHES, Individually and
                                          as Co-Documentation Agent

                                       By: /s/ Robert S. Taylor, Jr.
                                          -------------------------------------
                                          Title: Senior Vice President

                                       By: /s/ Andrew P, Lusk
                                          -------------------------------------
                                          Title: Vice President



                                       UBS AG, Cayman Island Branch

                                       By: /s/ Thomas R. Salzano
                                          -------------------------------------
                                          Title: Director
                                                 Banking Products Services, US


                                       By: /s/ Barbara Ezell-McMichael
                                          -------------------------------------
                                          Title: Associate Director
                                                 Banking Products Services, US



                                       ABN AMRO BANK N.V.

                                       By: /s/ Eric Oppenheimer
                                          -------------------------------------
                                          Title: Vice President

                                       By: /s/ Todd J. Miller
                                          -------------------------------------
                                          Title: Assistant Vice President



                                       SAN PAOLO IMI S.P.A.

                                       By: /s/ Renato Carducci
                                          -------------------------------------
                                          Title: General Manager

                                       By: /s/ Luca Sacchi
                                          -------------------------------------
                                          Title: Vice President



                                       U.S. BANK N.A.

                                       By: /s/ Michael P. Dickman
                                          -------------------------------------
                                          Title: Assistant Vice President



                                       WACHOVIA BANK, N.A.

                                       By: /s/ Joseph C. Bossong, Jr.
                                          -------------------------------------
                                          Title: Director



                                       THE NORTHERN TRUST COMPANY

                                       By: /s/ John Konstantos
                                          -------------------------------------
                                          Title: Vice President



                                       BANCA NAZIONALE DEL LAVORO, S.P.A.,
                                           NEW YORK BRANCH

                                       By: /s/ Francesco Di Mario
                                          -------------------------------------
                                          Title: Vice President

                                       By: /s/ Juan Cortes
                                          -------------------------------------
                                          Title: Vice President

<PAGE>

                                       THE BANK OF NEW YORK

                                       By: /s/ Thomas J. McCormack
                                          -------------------------------------
                                          Title: Vice President



                                       MELLON BANK, N.A.

                                       By: /s/ Marla A. DeYulis
                                          -------------------------------------
                                          Title: Assistant Vice President



                                       BANCO POPULAR DE PUERTO RICO, NEW YORK
                                          BRANCH

                                       By: /s/ Hector J. Gonzalez
                                          -------------------------------------
                                          Title: Vice President



                                       THE GOVERNOR AND COMPANY OF THE BANK
                                           OF IRELAND

                                       By: /s/ F. McDonald
                                          -------------------------------------
                                          Title: Director



                                       BANCO BILBAO VIZCAYA ARGENTARIA, S.A.,
                                           NEW YORK BRANCH

                                       By: /s/ Jay Levit
                                          -------------------------------------
                                          Title: Vice President, Global
                                          Corporate Banking

                                       By: /s/ John Martini
                                          -------------------------------------
                                          Title: Vice President, Corporate
                                          Banking