Exhibit 10.1

                                    AMENDMENT
                                       TO
                         TRIANGLE PHARMACEUTICALS, INC.
                            1996 STOCK INCENTIVE PLAN
                (AS AMENDED AND RESTATED THROUGH MARCH 27, 1998)

      THIS AMENDMENT is made and entered into this 18th day of May, 2001,
effective as stated below, by Triangle Pharmaceuticals, Inc., a Delaware
corporation (the "Corporation").

                              W I T N E S S E T H:

      WHEREAS, the Corporation has previously adopted the Triangle
Pharmaceuticals, Inc. 1996 Stock Incentive Plan, as last amended and restated
through March 27, 1998 ("Plan");

      WHEREAS, Article Six, Section IV, of the Plan provides, in part, that the
Board of Directors of the Corporation (the "Board") shall have complete and
exclusive power and authority to amend or modify the Plan in any or all
respects, subject to stockholder approval if required by applicable laws or
regulations or otherwise required by the Board;

      WHEREAS, on March 6, 2001, the Board authorized the following amendments
to the Plan, subject to the approval of the stockholders of the Corporation at
the 2001 annual meeting of the Corporation:

1.    an increase in the number of shares of common stock reserved for issuance
      under the Plan by 1,500,000 shares effective January 1, 2002;

2.    an increase in the number of shares of common stock reserved for issuance
      under the Plan by an additional 1,500,000 shares effective January 1,
      2003; and

3.    an increase in the number of shares covered by each automatic stock option
      grant to a non-employee director under the Plan as follows, effective for
      automatic grants made with respect to the 2001 and future annual meetings
      of the Corporation's stockholders: (A) upon the initial election or
      appointment of a non-employee director, the director will receive an
      option to purchase 7,500 shares of the Corporation's common stock and,
      during any partial year and for each full year of the term for which the
      director is elected or appointed, the director will receive an option to
      purchase an additional 7,500 shares of the Corporation's common stock ,
      and (B) upon the re-election of a non-employee director, the director will
      receive an option to purchase 7,500 shares of the Corporation's Common
      Stock during any partial year and for each full year of the term for which
      the director is re-elected; and

      WHEREAS, on May 18, 2001 the stockholders of the Corporation approved such
amendments at the 2001 annual meeting of the Corporation.

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      NOW, THEREFORE, the Corporation hereby amends the Plan as follows:

I. The following hereby amends and restates in its entirely Article One, Section
V.A of the Plan:

            "The stock issuable under the Plan shall be shares of authorized but
      unissued or reacquired Common Stock, including shares repurchased by the
      Corporation on the open market. The maximum number of shares of Common
      Stock reserved for issuance over the term of the Plan shall not exceed a
      total of 5,699,829 shares. Effective January 1, 2002, the maximum number
      of shares of Common Stock reserved for issuance over the term of the Plan
      shall be increased by 1,500,000, not to exceed a total of 7,199,829 shares
      and effective January 1, 2003 the maximum number of shares of Common Stock
      reserved for issuance over the term of the Plan shall be increased by
      1,500,000, not to exceed a total of 8,699,829 shares."

II. The following hereby amends and restates in its entirety Article Five,
Section I.A. of the Plan:

      "A. GRANT DATES. Effective with the 2001 Annual Meeting, (i) on the date
      that each non-employee Board member is first elected or appointed to the
      Board, option grants shall be made to such non-employee Board member and
      (ii) on the date that each non-employee Board member is re-elected to the
      Board, option grants shall be made to such non-employee Board member. Each
      automatic option grant shall be a Non-Statutory Option. For each
      individual who is first elected or appointed as a non-employee Board
      member, the number of shares of Common Stock subject to the option shall
      be equal to 7,500 shares. Each non-employee Board member so elected shall,
      during any partial year and for each full year of the term for which the
      non-employee Board member is elected or appointed, also receive an option
      to purchase an additional 7,500 shares of Common Stock. Each non-employee
      Board member who is re-elected to the Board at any time after his or her
      initial term will receive, during any partial year and for each full year
      of the term for which the non-employee Board member is re-elected to the
      Board, an automatic grant of an option to purchase an additional 7,500
      shares of Common Stock. There shall be no limit on the number of such
      automatic grants any one Eligible Director may receive over his or her
      period of Board service, and non-employee Board members who have
      previously been in the employ of the Corporation (or any Parent or
      Subsidiary) or who have otherwise received a stock option grant from the
      Corporation prior to becoming a non-employee Board member shall be
      eligible to receive one or more such annual option grants over their
      period of continued Board service."


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III. The following hereby amends and restates in its entirety Article Six,
Section 3.D of the Plan:

            "D. On the Plan Effective Date, 2,200,000 shares of Common Stock
      were available for issuance over the term of the Plan. Such authorized
      share reserve was comprised of the number of shares which remained
      available for issuance, as of the Plan Effective Date, under the
      Predecessor Plan as last approved by the Corporation's stockholders,
      including the shares subject to the outstanding options incorporated into
      the Plan and the additional shares which were otherwise available for
      future grant, plus an additional increase of 500,000 shares authorized by
      the Board and subsequently approved by the stockholders prior to the
      Section 12 Registration Date.

            On December 4, 1997, the Board adopted an amendment to the Plan (the
      "1997 Amendment") to effect the following changes: (i) increase the
      maximum number of shares of Common Stock available for issuance over the
      term of the Plan by an additional 1,000,000 shares, and (ii) implement an
      automatic share increase feature pursuant to which the number of shares of
      Common Stock available for issuance under the Plan automatically increased
      on January 1 of each of the calendar years 1999, 2000 and 2001 by an
      amount equal to four percent (4%) of the total number of shares of Common
      Stock issued and outstanding on December 31st of the immediately preceding
      calendar year; provided, however, that in no event did any such annual
      increase exceed the difference between (x) 1,000,000 shares and (y) the
      number of shares of Common Stock available for future option grants under
      the Plan on such December 31 (net of all outstanding options and unvested
      stock issuances). The increase under this provision was 629,723 shares
      effective January 1, 1999, 905,791 shares effective January 1, 2000, and
      964,315 shares effective January 1, 2001, for an aggregate of 2,499,829
      over this three year period.

            In addition, on March 27, 1998, the Board adopted an amendment to
      the Plan (the "1998 Amendment") to effect the following change: under the
      Automatic Option Grant Program, effective with the 1998 Annual Meeting (A)
      automatically grant to each individual who is first appointed or elected
      as a non-employee Board member an option to purchase shares of Common
      Stock in an amount equal to 2,000 shares of Common Stock plus 2,000 shares
      for any partial year and for each full year of the term for which the
      non-employee Board member is first appointed or elected, and (B)
      automatically grant to each individual who is re-elected to serve as a
      non-employee Board member an option to purchase 2,000 shares of Common
      Stock for each full year of the term for which the non-employee Board
      member is re-elected to the Board. The 1997 Amendment and the 1998
      Amendment were approved by the stockholders of the Corporation at the 1998
      Annual Meeting.

            In addition, on March 6, 2001, the Board unanimously adopted an
      amendment to the Plan (the "2001 Amendment") to (i) increase the maximum


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      number of shares of Common Stock available for issuance over the term of
      the Plan by an additional 1,500,000 shares effective January 1, 2002, (ii)
      increase the maximum number of shares of Common Stock available for
      issuance over the term of the Plan by an additional 1,500,000 shares
      effective January 1, 2003 and (iii) under the Automatic Option Grant
      Program, effective with the 2001 Annual Meeting (A) automatically grant to
      each individual who is first appointed or elected as a non-employee Board
      member an option to purchase 7,500 shares of Common Stock (B) during any
      partial year and for each full year of the term for which the non-employee
      Board member is first appointed or elected, automatically grant an option
      to purchase 7,500 shares of Common Stock, and (C) during each full year of
      the term for which the non-employee Board member is re-elected to the
      Board, automatically grant to each individual who is re-elected to serve
      as a non-employee Board member an option to purchase 7,500 shares of
      Common Stock. The 2001 Amendment was approved by the stockholders of the
      Corporation at the 2001 Annual Meeting."

IV. This Amendment does not supersede the terms and conditions of the Plan,
except to the extent expressly described herein.

      IN WITNESS WHEREOF, the Corporation has caused this Amendment to be
executed by its duly authorized officer, all as of the day and year first above
written.

                                                  TRIANGLE PHARMACEUTICALS, INC.


                                                  By: /s/ R. Andrew Finkle
                                                      --------------------------
                                                  R. Andrew Finkle
                                                  Executive Vice President,
                                                  General Counsel and Secretary


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