Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. 1350

(SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002)

I, David Burgstahler, President and Chief Executive Officer of Avista Healthcare Public Acquisition Corp. (the “Company”), certify, pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, 18 U.S.C. Section 1350, that, to the best of my knowledge:

(1) the Quarterly Report on Form 10-Q of the Company for the quarterly period ended June 30, 2018 (the “Report”) fully complies with the requirements of Section 13 (a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m(a) or 78o(d)); and

(2) the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: August 7, 2018
	/s/ David Burgstahler
	David Burgstahler
	President and Chief Executive Officer

The foregoing certification is being furnished solely pursuant to 18 U.S.C. 1350 (as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002) and is not being filed as part of the Report or as a separate disclosure document.