Animal and human data suggest a relationship between bile acids, especially secondary bile acids, and colorectal cancer. Ursodeoxycholic acid, a synthetic bile acid, has been shown in animal and in vitro studies to reduce the risk of colonic dysplasia and cancer development. Human trials have focused on patients with history of adenoma, inflammatory bowel disease, primary sclerosing cholangitis, and primary biliary cirrhosis. Some studies suggest that ursodeoxycholic may reduce the colorectal cancer risk, but to date the studies are small, mostly retrospective, and lacking in solid evidence to support use of UDCA for colorectal cancer chemoprophylaxis.