Exhibit 5.1


  12670 High Bluff Drive
  San Diego, California 92130
  Tel: +1.858.523.5400 Fax: +1.858.523.5450
  Beijing    Moscow
  Boston    Munich
  Brussels    New York
  Century City    Orange County
  Chicago    Paris
  Dubai    Riyadh
March 9, 2018   Düsseldorf    Rome
  Frankfurt    San Diego
  Hamburg    San Francisco
  Hong Kong    Seoul
  Houston    Shanghai
  London    Silicon Valley
  Los Angeles    Singapore
  Madrid    Tokyo
  Milan    Washington, D.C.

Conatus Pharmaceuticals Inc.

16745 West Bernardo Drive, Suite 200

San Diego, California 92127


  Re: Registration Statement on Form S-8; 2,525,000 Shares of Common Stock, par value $0.0001 per share

Ladies and Gentlemen:

We have acted as special counsel to Conatus Pharmaceuticals Inc., a Delaware corporation (the “Company”), in connection with the proposed issuance of an aggregate of 2,525,000 shares (the “Shares”) of common stock, par value $0.0001 per share, of the Company, of which 2,000,000 Shares are issuable pursuant to the Company’s 2013 Incentive Award Plan (the “2013 Plan”) and 525,000 Shares are issuable pursuant to that certain Non-Qualified Inducement Stock Option Grant Notice and Stock Option Agreement dated August 31, 2017 by and between the Company and Keith W. Marshall, Ph.D., M.B.A (the “Inducement Option Agreement”). The Shares are included in a Registration Statement on Form S-8 under the Securities Act of 1933, as amended (the “Act”), filed with the Securities and Exchange Commission (the “Commission”) on March 9, 2018 (the “Registration Statement”). This opinion is being furnished in connection with the requirements of Item 601(b)(5) of Regulation S-K under the Act, and no opinion is expressed herein as to any matter pertaining to the contents of the Registration Statement, other than as expressly stated herein with respect to the issuance of the Shares.

As such counsel, we have examined such matters of fact and questions of law as we have considered appropriate for purposes of this letter. With your consent, we have relied upon certificates and other assurances of officers of the Company and others as to factual matters without having independently verified such factual matters. We are opining herein as to the General Corporation Law of the State of Delaware, and we express no opinion with respect to any other laws.

March 9, 2018

Page 2




In our examination, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals and the conformity to authentic original documents of all documents submitted to us as copies.

Subject to the foregoing and the other matters set forth herein, it is our opinion that, as of the date hereof, when the Shares shall have been duly registered on the books of the transfer agent and registrar therefor in the name or on behalf of the recipients, or certificates representing the Shares (in the form of the specimen certificate incorporated by reference as an exhibit to the Company’s most recent Annual Report on Form 10-K) have been manually signed by an authorized officer of the transfer agent and registrar therefor, and subject to the Company completing all actions and proceedings required on its part to be taken prior to the issuance of the Shares, and when the Shares have been issued by the Company in the circumstances contemplated by the 2013 Plan or the Inducement Option Agreement for legal consideration in excess of par value, the issuance of the Shares will have been duly authorized by all necessary corporate action of the Company, and the Shares will be validly issued, fully paid and nonassessable. In rendering the foregoing opinion, we have assumed that the Company will comply with all applicable notice requirements regarding uncertificated shares provided in the General Corporation Law of the State of Delaware.

This opinion is for your benefit in connection with the Registration Statement and may be relied upon by you and by persons entitled to rely upon it pursuant to the applicable provisions of the Act. We consent to your filing this opinion as an exhibit to the Registration Statement. In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Act or the rules and regulations of the Commission thereunder.

Very truly yours,