Exhibit 23.1
Consent of Independent Registered Public Accounting Firm
We hereby consent to the incorporation by reference in this Registration Statement on Form S-3 of our report dated March 24, 2015 relating to the financial statements, which appears in Mast Therapeutics, Inc.’s Annual Report on Form 10-K for the year ended December 31, 2014. We also consent to the reference to us under the heading “Experts” in such Registration Statement.
| /s/ PricewaterhouseCoopers LLP |
| San Diego, California |
| March 24, 2015 |
