EXHIBIT 4.1

                            STOCK PURCHASE WARRANT
       TO PURCHASE 2,000,000 SHARES OF COMMON STOCK, $.001 PAR VALUE OF
                               CATALYTICA, INC.



THE SALE, ASSIGNMENT OR TRANSFER OF THIS WARRANT IS PROHIBITED OTHER THAN SALES,
ASSIGNMENTS OR TRANSFERS THAT ARE IN COMPLIANCE WITH THE TERMS AND CONDITIONS OF
A WARRANT PURCHASE AGREEMENT BY AND AMONG THE CORPORATION, CATALYTICA
PHARMACEUTICALS, INC. AND GLAXO WELLCOME INC.  A COPY OF SUCH AGREEMENT MAY BE
OBTAINED UPON WRITTEN REQUEST TO THE SECRETARY OF THE CORPORATION.  THE RIGHTS
TO ACQUIRE SHARES REPRESENTED BY THIS WARRANT HAVE BEEN ACQUIRED FOR INVESTMENT
AND NOT WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR DISTRIBUTION THEREOF.


WARRANT NO. GW-1
ISSUE DATE:  July 31, 1997



     THIS CERTIFIES that, for value received, Glaxo Wellcome Inc. is entitled,
upon the terms and subject to the conditions hereinafter set forth, at any time
on or after the date hereof and during the term of this Warrant, to subscribe
for and purchase from Catalytica, Inc., a Delaware corporation (the "Company"),
up to 2,000,000 of the fully paid and non-assessable shares ("Shares") of the
Company's Common Stock, $.001 par value ("Common Stock") at a purchase price of
$12.00 per share ("Purchase Price").  The Purchase Price and the number of
shares for which the Warrant is exercisable shall be subject to adjustment as
provided herein.  This Warrant is being issued pursuant to the Warrant Purchase
Agreement dated June 25, 1997.

1.        Transferability of Warrant.  Prior to its expiration hereof, this 
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     Warrant may be held only by Glaxo Wellcome and may not be transferred,
     assigned or sold to any other individual or entity other than by transfers,
     assignments or sales that are in compliance with the terms and conditions
     of the warrant purchase agreement by and among the Corporation, Catalytica
     Pharmaceuticals, Inc. and Glaxo Wellcome Inc. A copy of such agreement may
     be obtained upon written request to the secretary of the corporation.

2.        Exercise of Warrant.
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     a.        The term of this Warrant shall commence on July 31, 1997, and
          will expire at the close of business California time on July 31, 2003.
          The Warrant may be exercised for all or part of the Shares, in whole
          or in part, at any time during the term of this 

 
          Warrant by the surrender of this Warrant and a duly executed Notice of
          Warrant Exercise in the form of Exhibit 1 at the office of the Company
          at 430 Ferguson Drive, Mountain View, California 94043 (or such other
          office or agency of the Company as it may designate by notice in
          writing to the holder of this Warrant), and upon payment of the
          Purchase Price of the Shares thereby purchased (by wire transfer or by
          certified check or by bank draft payable to the order of the Company
          in an amount equal to the Purchase Price of the Shares thereby
          purchased); whereupon the holder of this Warrant shall be entitled to
          receive a certificate for the number of Shares so purchased. The
          Shares so purchased shall be deemed issued to such holder as the
          record owner of such Shares as of the close of business California
          time on the date on which this Warrant shall have been exercised.

     b.        In the event of any exercise of the purchase right represented by
          this Warrant, certificates for the Shares so purchased shall be
          delivered to the holder hereof within fifteen (15) days of the
          effective date of such purchase and, unless this Warrant has been
          fully exercised or expired, a new Warrant representing the portion of
          the Shares, if any, with respect to which this Warrant shall not then
          have been exercised shall also be issued to the holder hereof within
          such fifteen (15) day period. Upon the effective date of such
          purchase, the holder shall be deemed to be the holder of record of the
          Shares, notwithstanding that Certificates representing the Shares
          shall not then be actually delivered to such holder or that such
          Shares are not then set forth on the stock transfer books of the
          Company.

     c.        The Company covenants that all Shares that may be issued upon the
          exercise of rights represented by this Warrant will, upon exercise in
          accordance with the terms of this Warrant, be fully paid and
          nonassessable and free from all taxes, liens and charges in respect of
          the issue (other than taxes in respect of any transfer occurring
          contemporaneously with such issue).

3.        No Fractional Shares or Scrip.  No fractional shares or scrip 
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     representing fractional shares shall be issued upon the exercise of this
     Warrant.

4.        Adjustments.  The purchase rights set forth herein are subject to
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     adjustment as provided below.

     a.        Stock Splits, Stock Combinations and Stock Dividends.  If the 
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          Company shall at any time subdivide the outstanding shares of Common
          Stock, then the number of shares of Common Stock for which this
          Warrant is exercisable immediately prior to that subdivision (the
          "Number of Warrant Shares") shall be proportionately increased and the
          purchase price therefor proportionately decreased, and if the Company
          shall at any time combine the outstanding shares of Common Stock, then
          the Number of Warrant Shares shall be proportionately decreased and
          the purchase price therefor proportionately increased. If the Company
          shall at any time declare or pay a dividend in shares of Common Stock
          to holders of its outstanding Common Stock, the Number

 
          of Warrant Shares purchasable upon exercise of this Warrant
          immediately prior thereto shall be adjusted so that the holder of this
          Warrant shall be entitled to receive the kind and number of Shares or
          other securities of the Company which the holder would have owned or
          have been entitled to receive had such Warrant been exercised in
          advance thereof. Any adjustment under this Section 4.1 shall become
          effective at the close of business on the date the subdivision or
          combination becomes effective.

     b.        Reclassification, Exchange and Substitution.  If the Common Stock
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          issuable on exercise of this Warrant shall be changed into the same or
          a different number of shares of any other class or classes of stock,
          whether by capital reorganization, reclassification, or otherwise
          (other than a subdivision or combination of shares provided for
          above), then the holder of this Warrant shall, upon its exercise, be
          entitled to receive, in lieu of the Common Stock that the holder would
          have become entitled to receive but for such change, that number of
          shares of such other class or classes of stock that is equivalent to
          the number of shares of Common Stock that would have been subject to
          receipt by the holder on exercise of this Warrant immediately prior to
          that change.

     c.        Reorganizations, Mergers or Consolidations.  If at any time there
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          shall be a capital reorganization of the Common Stock (other than a
          subdivision, combination, reclassification or exchange of shares
          provided for elsewhere in this Warrant) or merger or consolidation of
          the Company with or into another corporation, then as a part of such
          reorganization, merger or consolidation, lawful provision shall be
          made so that the holder of this Warrant shall thereafter be entitled
          to receive upon exercise of this Warrant, during the period specified
          in this Warrant, the number of shares of stock or other securities or
          property of the Company, or of the successor corporation resulting
          from such merger or consolidation, to which a holder of the Common
          Stock deliverable upon exercise of this Warrant would have been
          entitled on such capital reorganization, merger or consolidation if
          this Warrant had been exercised immediately prior to that
          reorganization, merger or consolidation.  In any such case,
          appropriate adjustment shall be made in the application of the
          provisions of this Warrant with respect to the rights of the holder
          after the reorganization, merger or consolidation to the end that the
          provisions of this Warrant (including adjustment of the Number of
          Warrant Shares then in effect) shall be applicable after that event in
          a manner as nearly equivalent as may be practicable.

     d.        Notice of Adjustments.  The Company shall promptly give written 
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          notice of each adjustment or readjustment of the number of shares of
          Common Stock or other securities issuable upon exercise of this
          Warrant, by first class mail, postage prepaid, to the registered
          holder of this Warrant at the holder's address as shown on the
          Company's books. This notice shall state that adjustment or
          readjustment and show in reasonable detail the facts on which that
          adjustment or readjustment is based.

 
     e.       No Change Necessary.  The form of this Warrant need not be changed
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          because of any adjustment in the number of shares of Common Stock
          issuable upon its exercise.  A Warrant issued after any adjustment on
          exercise or upon replacement may continue to express the same number
          of shares of Common Stock as are stated on this Warrant as initially
          issued, and such number of shares shall be considered to have been so
          changed as of the close of business on the date of adjustment.

     f.        Reservation of Stock.  The Company covenants that it will at all 
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          times reserve and keep available, solely for issuance upon exercise of
          this Warrant, all shares of its Common Stock from time to time
          issuable upon exercise of this Warrant, and if at any time the number
          of authorized but unissued shares of Common Stock shall not be
          sufficient to effect the exercise of this Warrant, the Company will
          take such corporate action as may, in the opinion of its counsel, be
          necessary to increase its authorized but unissued shares of Common
          Stock to such number of shares as shall be sufficient for such
          purpose.

5.        Notices of Record Date.  In the event of any taking by the Company of 
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     a record of the holders of any class of securities for the purpose of
     determining the holders thereof who are entitled to receive any dividend or
     other distribution in cash or securities or property other than shares of
     Common Stock, the Company shall mail to the holder of this Warrant at least
     fifteen days prior to the date specified therein, a notice specifying the
     date on which any such record is to be taken for the purpose of such
     dividend or distribution.

6.        Charges, Taxes and Expenses.  Issuance of certificates for shares of 
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     Common Stock upon the exercise of this Warrant shall be made without charge
     to the holder hereof for any issue or transfer tax or other incidental
     expense in respect of the issuance of such certificate, all of which taxes
     and expenses shall be paid by the Company. Such certificates shall be
     issued in the name of the holder of this Warrant.

7.        No Rights as Stockholder.  This Warrant does not entitle the holder 
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     to any voting rights or other rights as a stockholder of the Company prior
     to the exercise of this Warrant.

8.        Investment Representations.  The holder of this Warrant by receiving 
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     this Warrant makes the representations contained in paragraph 2.1 of the
     Warrant Purchase Agreement dated July 31, 1997.

     a.        Legends.  Each certificate representing Shares shall be endorsed 
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          with the following legend (in addition to any legend required by
          applicable state securities laws):

          THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR
          INVESTMENT AND NOT WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR
          DISTRIBUTION THEREOF. NO SUCH SALE OR DISPOSITION MAY BE EFFECTED
          WITHOUT AN 

 
          EFFECTIVE REGISTRATION STATEMENT RELATED THERETO OR AN OPINION OF
          COUNSEL REASONABLY SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION
          IS NOT REQUIRED UNDER THE SECURITIES ACT OF 1933.

The Company need not register a transfer of Shares unless the conditions
specified in the foregoing legend are satisfied.  The Company may also instruct
its transfer agent not to register the transfer of any of the Shares unless the
conditions specified in the foregoing legend are satisfied.

     b.        Removal of Legends and Transfer Restrictions.  The legend 
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          relating to the Act endorsed on a stock certificate pursuant to
          Section 8.1 and the stop transfer instructions with respect to the
          Shares represented by such certificate shall be removed and the
          Company shall issue a certificate without such legend to the holder of
          such Shares if such holder provides to the Company an opinion of
          counsel for such holder of the Shares reasonably satisfactory to the
          Company or a no-action letter or interpretive opinion of the staff of
          the Securities and Exchange Commission to the effect that a public
          sale, transfer or assignment of such Shares may be made without
          registration and without compliance with any restriction such as Rule
          144.

9.        Loss, Theft, Destruction or Mutilation of Warrant.  Upon receipt by 
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     the Company of evidence reasonably satisfactory to it of the loss, theft,
     destruction or mutilation of this Warrant, and in case of loss, theft or
     destruction, of indemnity or security reasonably satisfactory to it, and
     upon reimbursement to the Company of all reasonable expenses incidental
     thereto, and upon surrender and cancellation of this Warrant, if mutilated,
     the Company will make and deliver a new Warrant of like tenor and dated as
     of such cancellation, in lieu of this Warrant.

10.       Saturdays, Sundays, Holidays, etc.  If the last or appointed day for 
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     the taking of any action or the expiration of any right required or granted
     herein shall be a Saturday or a Sunday or shall be a legal holiday, then
     such action may be taken or such right may be exercised on the next
     succeeding day not a legal holiday.

11.       Miscellaneous.
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          i.        The provisions of this Warrant shall be construed and shall
               be given effect in all respects as if it had been issued and
               delivered by the Company on the date of this Warrant. This
               Warrant shall be binding upon any successors or assigns of the
               Company. This Warrant shall constitute a contract under the laws
               of the State of Delaware and for all purposes shall be construed
               in accordance with and governed by the laws of said state
               (irrespective of its choice of law principles).

 
          ii.       The holder acknowledges that the Common Stock acquired upon
               the exercise of this Warrant shall have restrictions upon its
               resale imposed by state and federal securities laws described in
               the Warrant Purchase Agreement.

     IN WITNESS WHEREOF, Catalytica, Inc. has caused this Warrant to be executed
by its duly authorized officer.

Dated:  July 31, 1997

                                       CATALYTICA, INC.


                                       /S/ Ricardo B. Levy
                                       -----------------------------
                                       Ricardo B. Levy
                                       President and Chief Executive Officer

 
                                   Exhibit 1
                                   ---------

                           NOTICE OF WARRANT EXERCISE
                           --------------------------


To:  CATALYTICA, INC.


     (1) The undersigned hereby elects to purchase _____________ shares of
Common Stock of Catalytica, Inc. pursuant to the terms of the attached Warrant,
and tenders herewith payment of the purchase price in full.

     (2) Please issue a certificate or certificates representing said shares of
Common Stock in the name of the undersigned.  The undersigned's tax
identification number is _____________.

     (3) The undersigned represents that the aforesaid shares of Common Stock
are being acquired for the account of the undersigned for investment and not
with a view to, or for resale in connection with, the distribution thereof.  The
undersigned confirms and remakes as of the date of this notice the
representations contained in Section 2.1 of the Warrant Purchase Agreement dated
__________, 1997 with respect to such Shares of Common Stock.


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(Date)                                   (Signature)