EXHIBIT 5

             OPINION AND CONSENT OF BROBECK, PHLEGER & HARRISON LLP

                                 March 22, 1999

Triangle Pharmaceuticals, Inc.
4 University Place
4611 University Drive
Durham, NC  27707

          Re:  Triangle Pharmaceuticals, Inc. - Registration Statement for
               Offering of an 629,723 Shares of Common Stock

Ladies and Gentlemen:

     We have acted as counsel to Triangle Pharmaceuticals, Inc., a Delaware
corporation (the "Company"), in connection with the registration on Form S-8
(the "Registration Statement") under the Securities Act of 1933, as amended, of
629,723 shares of common stock of the Company (the "Shares") and related stock
options under the Company's 1996 Stock Incentive Plan (the "Incentive Plan").

     This opinion is being furnished in accordance with the requirements of Item
8 of Form S-8 and Item 601(b)(5)(i) of Regulation S-K.

     We have reviewed the Company's charter documents and the corporate
proceedings taken by the Company in connection with the establishment and
administration of the Incentive Plan. Based on such review, we are of the
opinion that if, as and when the Shares are issued and sold (and the
consideration therefor received) pursuant to the provisions of option agreements
or stock issuance agreements duly authorized under the Incentive Plan and in
accordance with the Registration Statement, such Shares will be duly authorized,
legally issued, fully paid and nonassessable.

     We consent to the filing of this opinion letter as Exhibit 5 to the
Registration Statement.

     This opinion letter is rendered as of the date first written above and we
disclaim any obligation to advise you of facts, circumstances, events or
developments which hereafter may be brought to our attention and which may
alter, affect or modify the opinion expressed herein. Our opinion is expressly
limited to the matters set forth above and we render no opinion, whether by
implication or otherwise, as to any other matters relating to the Company, the
Incentive Plan or the Shares.


                                Very truly yours,


                              /s/ Brobeck, Phleger & Harrison LLP

                              BROBECK, PHLEGER & HARRISON LLP