November 15, 2018

Ben Silbert
General Counsel and Secretary
Avista Healthcare Public Acquisition Corp.
65 East 55th Street
18th Floor
New York, NY 10022

       Re: Avista Healthcare Public Acquisition Corp.
           Amendment No. 2 to Registration Statement on Form S-4
           Filed November 5, 2018
           File No. 333-227090

Dear Mr. Silbert:

      We have reviewed your amended registration statement and have the
following
comments. In some of our comments, we may ask you to provide us with
information so we
may better understand your disclosure.

       Please respond to this letter by amending your registration statement
and providing the
requested information. If you do not believe our comments apply to your facts
and
circumstances or do not believe an amendment is appropriate, please tell us why
in your
response.

       After reviewing any amendment to your registration statement and the
information you
provide in response to these comments, we may have additional comments. Unless
we note
otherwise, our references to prior comments are to comments in our October 24,
2018 letter.

Amendment No. 2 to Registration Statement on Form S-4 filed November 5, 2018

Risk Factors
Risks Related to AHPAC and the Business Combination
Certain members of the AHPAC Board and AHPAC's officers are also members of the
investment committee of the PIPE Investors, page 72

1.     We note your response to comment 1. Please expand your disclosure to
clarify that the
       terms of the merger, including the exchange ratio of 2.03 AHPAC shares
for each share of
       Organogenesis, were negotiated by Messrs. Dean and Burgstahler who, at
the same time,
 Ben Silbert
FirstName LastNameBen Acquisition Corp.
Avista Healthcare Public Silbert
Comapany 15, 2018
November NameAvista Healthcare Public Acquisition Corp.
November 15, 2018 Page 2
Page 2
FirstName LastName
         approved the private investment at the effective price of $5.91 per
share and controlled the
         Sponsor, which, in turn, surrendered AHPAC shares to provide
Organogenesis with equity
         at an effective price of $7.035 per share, and that such terms may not
reflect the value of
         Organogenesis stock if it were a publicly-traded company.
2.       Please clarify what it means to "primarily" represent AHPAC in the
negotiations.
         Additionally, if accurate, please specifically state that Thompson
Dean, David
         Burgstahler, Sriram Venkataraman and Robert Girardi are investors in
the PIPE
         investment.
The Business Combination, page 95

3.       We note your response to comment 5 with respect to the proxy statement
regarding your
         October 4, 2018 extraordinary general meeting. While your response did
not address the
         basis for your belief that your redemption offer was not required to
comply with the
         provision of Exchange Act Rule 13e-4 and Regulation 14E, we do not
have any follow up
         comments about this issue at this time. Our decision to not issue
additional comments
         should not be interpreted to mean that we either agree or disagree
with your response.
Background of the Business Combination , page 98

4.       Please expand your disclosure to discuss the uninterested and
independent Directors
         approval of the transaction with the PIPE Investors as required by
Article 49.7(b) of your
         Articles of Association.
The AHPAC Board's Reasons for the Approved Business Combination, page 106

5.       Please expand your disclosure to highlight the lack of an independent
third party fairness
         or valuation advisor in determining the value of Organogenesis.
6.       We note that your description of the comparable companies analysis
also compared
         average annual percentage revenue growth and 2019 estimated gross
margin percentages
         for the comparable companies. Please present the results from this
analysis.
AHPAC's Management's Discussion and Analysis of Financial Condition and Results
of
Operations
Contractual Obligations, page 168

7.       You disclose the following on page 22 of Form 10-Q for the period
ended September 30,
         2018: "Pursuant to a deferred fee letter, dated as of August 17, 2018,
the Underwriters
         agreed that, in the event the deferred discount becomes payable upon
the completion of a
         business combination, such amount will be reduced to $5,128,205. The
deferred
         underwriting commissions held in the Trust Account will be forfeited
in the event we do
         not complete a business combination, subject to the terms of the
Underwriting Agreement.
         The Underwriters are not entitled to any interest accrued on the
deferred underwriting
         commissions." You also disclose on page 13 of the Form 10-Q that "The
Deferred
 Ben Silbert
Avista Healthcare Public Acquisition Corp.
November 15, 2018
Page 3
      Commission will be forfeited if the Company is unable to complete a
business
      combination in the prescribed time." Please address the following:
        Please revise your Form S-4 to discuss the updated terms in the
deferred fee letter, and
         clearly disclose the reasons for the deferred underwriting amounts
forfeited by the
         underwriters to date.
        Clearly disclose the revised date for completing a business combination
after which
         the remaining deferred underwriting fee of $5,128,205 will be
forfeited.
       You may contact Keira Nakada at 202-551-3659 or Kevin Vaughn at
202-551-3494 if
you have questions regarding comments on the financial statements and related
matters. Please
contact Christine Westbrook at 202-551-5019 or Suzanne Hayes at 202-551-3675
with any other
questions.



                                                           Sincerely,
FirstName LastNameBen Silbert
                                                      Division of Corporation
Finance
Comapany NameAvista Healthcare Public Acquisition Corp.
                                                      Office of Healthcare &
Insurance
November 15, 2018 Page 3
cc:       Jackie Cohen, Esq.
FirstName LastName