EXHIBIT 23.1
Consent of Independent Registered Public Accounting Firm
We consent to the reference to our firm under the caption “Experts” and to the use of our report dated May 15, 2017, except for the retroactive effect of the 1-for-5.87 reverse stock split as described in Note 1, as to which the date is July , 2017, in Amendment No. 1 to the Registration Statement (Form S-1) and related Prospectus of Sienna Biopharmaceuticals, Inc. dated July 17, 2017.
Ernst & Young LLP
Los Angeles, California
July , 2017
The foregoing consent is in the form that will be signed upon the completion of the restatement of capital accounts described in Note 1 to the financial statements
/s/ Ernst & Young LLP
Los Angeles, California
July 17, 2017
