As filed with the Securities and Exchange Commission on December 29, 2003.

                                                      REGISTRATION NO. 333-25043

================================================================================

                UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                        POST-EFFECTIVE AMENDMENT NO. 2 TO
                                    FORM S-3
             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                          ENCYSIVE PHARMACEUTICALS INC.
             (Exact name of registrant as specified in its charter)

             DELAWARE                                         13-3532643
   (State or other jurisdiction                            (I.R.S. Employer
 of incorporation or organization)                      Identification Number)

                         6700 WEST LOOP SOUTH, 4TH FLOOR
                              BELLAIRE, TEXAS 77401
                                 (713) 796-8822

  (Address, including zip code, and telephone number, including area code, of
                   registrant's principal executive offices)


            BRUCE D. GIVEN, M.D.                          With copies to:
        ENCYSIVE PHARMACEUTICALS INC.                 PORTER & HEDGES, L.L.P.
       6700 WEST LOOP SOUTH, 4TH FLOOR               700 LOUISIANA, 35TH FLOOR
            BELLAIRE, TEXAS 77401                    HOUSTON, TEXAS 77002-2764
               (713) 796-8822                          ATTN: ROBERT G. REEDY
 (Name and address, including zip code,              TELEPHONE (713) 226-0647
    and telephone number, including area              TELECOPY (713) 226-0247
        code, of agent for service)


         Approximate date of commencement of proposed sale to the public: Not
applicable. Deregistration of unsold securities.

         If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box. [ ]

         If any of the securities being registered on this Form are to be
offered on a delayed or continuous basis pursuant to Rule 415 under the
Securities Act of 1933, other than securities offered only in connection with a
dividend or interest reinvestment plan, please check the following box. [ ]

         If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act of 1933, please check the
following box and list the Securities Act of 1933 registration statement number
of the earlier effective registration statement for the same offering.
[ ]______________

         If this Form is a post-effective amendment filed pursuant to Rule
462(c) under the Securities Act of 1933, check the following box and list the
Securities Act of 1933 registration statement number of the earlier effective
registration statement for the same offering. [ ] ______________

         If delivery of the prospectus is expected to be made pursuant to Rule
434, please check the following box. [ ]



DEREGISTRATION OF SECURITIES

         On April 11, 1997, Encysive Pharmaceuticals Inc (formerly Texas
Biotechnology Corporation) (the "Company") filed a registration statement on
Form S-3 (No. 333-25043) and on May 22, 1997, April 16, 1998 and May 14, 1998,
the Company filed amendments thereto (as amended, the "Registration Statement").
The Registration Statement registered for resale by the selling shareholders
named therein a total of 3,161,572 shares of the Company's common stock, par
value $.005 per share (the "Common Stock"). The Company's contractual
obligations to the selling shareholders to maintain the effectiveness of the
Registration Statement has expired. Pursuant to the undertaking contained in the
Registration Statement, the Company files this post-effective amendment to the
Registration Statement to terminate the Registration Statement and deregister
all of the shares of Common Stock registered for resale thereunder that remain
unsold as of the date hereof.





                                   SIGNATURES


         Pursuant to the requirements of the Securities Act of 1933, the
registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-3 and has duly caused this
post-effective amendment to the Registration Statement to be signed on its
behalf by the undersigned, thereunto duly authorized, in the City of Bellaire,
State of Texas on December 29, 2003.

                                           ENCYSIVE PHARMACEUTICALS INC.




                                           By:  /s/  BRUCE D. GIVEN, M.D.
                                              ----------------------------------
                                                Bruce D. Given, M.D.
                                                President and Chief Executive
                                                Officer

                                POWER OF ATTORNEY

         Each of the undersigned hereby appoints Bruce D. Given and Stephen L.
Mueller and each of them (with full power to act alone), as attorney and agents
for the undersigned, with full power of substitution, for and in the name, place
and stead of the undersigned, to sign and file with the Securities and Exchange
Commission under the Securities Act of 1933 any and all amendments and exhibits
to this registration statement and any and all applications, instruments and
other documents to be filed with the Securities and Exchange Commission
pertaining to the registration of the securities covered hereby, with full power
and authority to do and perform any and all acts and things whatsoever requisite
or desirable.

         Pursuant to the requirements of the Securities Act of 1933, this
registration statement has been signed below by the following persons in the
capacities and on the 29th day of December, 2003.



                           SIGNATURE                                                   TITLE
                           ---------                                                   -----
                                                            
                             *                                          Chairman of the Board of Directors
  ---------------------------------------------------------
                       John M. Pietruski

         /s/  BRUCE D. GIVEN, M.D.                               Director, President and Chief Executive Officer
  ---------------------------------------------------------             (Principal Executive Officer)
                     Bruce D. Given, M.D.

                             *                                 Director, Senior Vice President, Research and Chief
  ---------------------------------------------------------                     Scientific Officer
                   Richard A.F. Dixon, Ph.D.

                             *                                     Vice President, Finance and Administration,
  ---------------------------------------------------------                  Treasurer and Secretary
                      Stephen L. Mueller                           (Principal Financial and Accounting Officer)


                             *                                                       Director
  ---------------------------------------------------------
                     Ron J. Anderson, M.D.






                           SIGNATURE                                                   TITLE
                           ---------                                                   -----
                                                                                  

                             *
  ---------------------------------------------------------                          Director
                       Frank C. Carlucci

                             *
  ---------------------------------------------------------                          Director
                     Robert J. Cruikshank


  ---------------------------------------------------------                          Director
                     Suzanne Oparil, M.D.


  ---------------------------------------------------------                          Director
                     William R. Ringo, Jr.

                             *
  ---------------------------------------------------------                          Director
                    James A. Thomson, Ph.D.

                             *
  ---------------------------------------------------------                          Director
                   James T. Willerson, M.D.


  *By:     /s/  STEPHEN L. MUELLER
         --------------------------------------------------
         Stephen L. Mueller
         individually and as attorney-in-fact