Ursodiol tablets. Box containing oral tablets of ursodiol (ursodeoxycholic acid, UDCA), a drug prescribed as a treatment for gallstones. Ursodiol is a naturally occurring secondary bile acid produced by intestinal bacteria in many species. In its purified form, it is used to treat or prevent several diseases of the liver or bile ducts. Ursodiol has been used as medical therapy in gallstone disease (cholelithiasis) and for biliary sludge. It helps to reduce the cholesterol saturation of bile and leads to gradual dissolution of cholesterol-rich gallstones. The name comes from the Latin for bear (genus Ursus) because ursodiol was first identified in bear bile.