Exhibit 99.2

                          ESSENTIAL THERAPEUTICS, INC.

                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350,
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Annual Report of Essential Therapeutics, Inc. (the
"Company") on Form 10-K for the period ending December 31, 2002 as filed with
the Securities and Exchange Commission on the date hereof (the "Report"), I,
Paul Mellett, Chief Financial Officer of the Company, certify, pursuant to 18
U.S.C. (S) 1350, as adopted pursuant to (S) 906 of the Sarbanes-Oxley Act of
2002, that:

     (1)  The Report fully complies with the requirements of section 13(a) or
          15(d) of the Securities Exchange Act of 1934; and

     (2)  The information contained in the Report fairly presents, in all
          material respects, the financial condition and results of operations
          of the Company.

                                                      /s/ Paul Mellett
                                                --------------------------------
                                                          Paul Mellett
                                                    Chief Financial Officer

March 31, 2003