Ironwood prices public offering of 5,250,000 shares of common stock

Ironwood Pharmaceuticals, Inc. (NASDAQ: IRWD) (the "Company") announced today the pricing of an underwritten public offering of 5,250,000 shares of its Class A common stock at a price of $15.09 per share to the public. All of the shares are being offered by Ironwood. The gross proceeds to Ironwood from this offering are expected to be approximately $79.2 million, before deducting underwriting discounts and commissions, and other estimated offering expenses payable by Ironwood. The offering is expected to close on February 15, 2012, subject to the satisfaction of customary closing conditions.

The Company intends to use the net proceeds from this offering for general corporate purposes, including to further strengthen its balance sheet in advance of the potential market launch of linaclotide (if approved).

J.P. Morgan Securities LLC and BofA Merrill Lynch are acting as joint active bookrunning managers and Morgan Stanley & Co. LLC is acting as passive bookrunning manager of the offering. Ladenburg Thalmann & Co., Inc. is acting as a co-manager of the offering. Ironwood has granted the underwriters a 30-day option to purchase up to an additional 15 percent of the amount of shares sold.