United States securities and exchange commission logo November 15, 2023 Sravan K. Emany Chief Financial Officer Ironwood Pharmaceuticals, Inc. 100 Summer Street, Suite 2300 Boston, MA 02110 Re: Ironwood Pharmaceuticals, Inc. Form 10-K for Fiscal Year Ended December 31, 2022 Form 8-K filed on February 16, 2023 File No. 001-34620 Dear Sravan K. Emany: We have limited our review of your filing to the financial statements and related disclosures and have the following comment. Please respond to this letter within ten business days by providing the requested information or advise us as soon as possible when you will respond. If you do not believe a comment applies to your facts and circumstances, please tell us why in your response. After reviewing your response to this letter, we may have additional comments. Form 8-K filed on February 16, 2023 Exhibits 1. Within this and your September 30, 2023 earnings release you present tables for the U.S. LINZESS Commercial Collaboration and US LINZESS Full Brand Collaboration Revenue/Expense Calculations. Please tell us how these tables reconcile to your annual and quarterly GAAP financial statements and quantify for us the differences, if necessary. Within your response, clearly explain what these tables represent; and tell us why you are presenting this information. In closing, we remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Sravan K. Emany Ironwood Pharmaceuticals, Inc. November 15, 2023 Page 2 Please contact Lynn Dicker at 202-551-3616 or Tara Harkins at 202-551-3639 with any questions. FirstName LastNameSravan K. Emany Sincerely, Comapany NameIronwood Pharmaceuticals, Inc. Division of Corporation Finance November 15, 2023 Page 2 Office of Life Sciences FirstName LastName