Exhibit 99.1

CONTACT:
Mark Skaletsky                                       Lisa Burns (Investors)
Chief Executive Officer, ext. 206                    Justin Jackson (Media)
Elizabeth Grammer                                    Burns McClellan
General Counsel, ext. 232                            (212) 213-0006
(718) 647-5554

                      Essential Therapeutics Announces Plan
               To Convert Series B Preferred Stock to Common Stock

WALTHAM, Mass., November 13, 2002 -- Essential Therapeutics, Inc. (NASDAQ: ETRX)
announced today that it has entered into separate Conversion Agreements with
certain holders of its outstanding shares of Series B Preferred Stock. The
holders of Series B Preferred Stock that have executed the Conversion Agreements
have agreed, subject to obtaining the requisite stockholder approval and the
satisfaction of certain other closing conditions, to vote all of the outstanding
shares held by them in favor of converting all outstanding shares of the
Company's Series B Preferred Stock into common stock. Each outstanding share of
Series B Preferred Stock shall convert into the number of shares of common stock
obtained by dividing the aggregate stated value of the outstanding Series B
Preferred Stock, plus any accrued and unpaid dividends, by a per share
conversion price of $0.75, subject to equitable and proportionate adjustment
following any stock split, reverse stock split, stock dividend or similar
transaction. The outstanding Series B Preferred Stock has an aggregate stated
value of $60 million, and therefore, if the conversion is consummated, the
Company will issue 80 million new shares of common stock in exchange for the
conversion of all 60,000 shares of Series B Preferred Stock outstanding. As a
result of this conversion no shares of Series B Preferred Stock will remain
outstanding and all the rights, preferences and privileges previously associated
with the Series B Preferred Stock will be extinguished, including, the right to
require the Company to repurchase the Series B Preferred Stock at a price of
$1,000 per share in a number of circumstances, including the passage of time and
the failure of the Company to maintain its listing on the Nasdaq National
Market.

The conversion of the outstanding shares of Series B Preferred Stock into common
stock is part of the Company's comprehensive plan to achieve compliance with the
Nasdaq National Market System listing criteria. For continued listing of the
Company's common stock on the Nasdaq National Market the Company is required to
maintain a minimum stockholders' equity of $10 million. As reported in the
Company's Quarterly Report on Form 10-Q for the quarter ended June 30, 2002, the
Company does not meet this minimum stockholders' equity criteria. The rights of
redemption associated with the Company's Series B Preferred Stock preclude the
stock from inclusion in stockholders' equity. The conversion of all outstanding
shares of Series B Preferred Stock will result in an increase in the Company's
stockholders' equity of approximately $53.0 million, resulting in a positive
stockholders' equity of approximately $41 million. The Company believes that
this action should enable the Company to achieve and sustain compliance with
Nasdaq's minimum stockholders' equity criteria. The reclassification of $53.0
million into stockholders' equity will also be reflected in the Company's
financial statements as an increase in the net loss applicable to common
stockholders for purpose of computing net loss per share of Common Stock.
Assuming a fair value of $1.00 per share of common stock at the time of the
conversion, the increase in net loss applicable to the common stock would be
$60.0 million.

The Company's stockholders will be asked to approve the conversion of the Series
B Preferred Stock into common stock at a Special Meeting of Stockholders that
will be called for such purpose. A number of related and dependent proposals
will also be put before the stockholders at the Special Meeting, including an
amendment to the Company's Restated Certificate of Incorporation to increase the
number of shares of



Common Stock that the Company is authorized to issue, and an amendment to the
Company's Restated Certificate of Incorporation to effect one of several
possible reverse stock splits ranging from a one-for-two reverse stock split to
a one-for-fifteen reverse stock split, if the Board of Directors of the Company
determines that such an amendment would be in the best interest of the Company
and its stockholders. The Company has filed its preliminary proxy materials with
the Securities and Exchange Commission and intends to mail proxy materials to
its stockholders following completion of the review period provided for the
Securities and Exchange Commission. If the Company's stockholders fail to
approve the conversion of all outstanding shares of Series B Preferred Stock,
then the Company does not expect that it would be able to maintain the listing
of its Common Stock on the Nasdaq National Market. In the event of delisting,
the terms of the Series B Preferred Stock provide that the Series B Preferred
Stockholders have the right to cause the Company to redeem their shares of
Series B Preferred Stock at a price of $1,000 per share. The redemption of all
60,000 shares of Series B Preferred Stock would result in the Company being
obligated to pay the holders of the Series B Preferred Stock an aggregate of
$60.0 million. The Company currently does not have the funds available to redeem
all of the outstanding shares of Series B Preferred Stock.

     About Essential Therapeutics

Essential Therapeutics is committed to the development of breakthrough
biopharmaceutical products for the treatment of life-threatening diseases. With
an emerging pipeline of lead programs and product candidates in the
anti-infective and hematology/oncology therapy areas, Essential Therapeutics is
dedicated to commercializing novel small molecule products addressing important
unmet therapeutic needs. Additional information on Essential Therapeutics can be
obtained at http://www.essentialtherapeutics.com.

Statements contained herein that are not historical fact may be forward-looking
statements within the meaning of Section 27A of the Securities Act of 1933 and
Section 21E of the Securities Exchange Act of 1934, that are subject to a
variety of risks and uncertainties. There are a number of important factors that
could cause actual results to differ materially from those projected or
suggested in any forward-looking statements made by the Company. These factors
include, but are not limited to, the Company's ability to meet and sustain
compliance with all of the list requirements of the Nasdaq National Market. For
a discussion of other risks and uncertainties affecting Essential Therapeutics'
business, see the Company's Quarterly Report on Form 10-Q for the quarter ended
June 30, 2002. Actual results and timing of certain events could differ
materially from those indicated in the forward-looking statements as a result of
these or other factors.

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