FOR IMMEDIATE RELEASE Ironwood Contact: Bionomics Contact: Susan Brady Dr Deborah Rathjen Corporate Communications CEO & Managing Director

617.621.8304 +61 8 8354 6101 sbrady@ironwoodpharma.com drathjen@bionomics.com.au

IRONWOOD PHARMACEUTICALS AND BIONOMICS ANNOUNCE COLLABORATION, RESEARCH, AND LICENSE AGREEMENT Companies to Collaborate on Central Nervous System Disorder Opportunity

CAMBRIDGE, Mass. and ADELAIDE, Australia January 5, 2012 - Ironwood Pharmaceuticals, Inc. (NASDAQ: IRWD) and Bionomics Limited (ASX: BNO) today announced that they entered into a collaboration, research, and licensing agreement that will enable Ironwood to develop and commercialize Bionomics' investigational anti