Ursodiol reduces cholesterol absorption and is used to dissolve gallstones.

Ursodiol, also known as ursodeoxycholic acid and the abbreviation UDCA, is one of the secondary bile acids, which are metabolic byproducts of intestinal bacteria. The drug reduces cholesterol absorption and is used to dissolve (cholesterol) gallstones in patients who want an alternative to surgery. The drug is very expensive, however, and if the patient stops taking it, the gallstones tend to recur if the condition that gave rise to their formation does not change. For these reasons, it has not supplanted surgical treatment by cholecystectomy.
Ursodeoxycholic acid is currently the only established drug for the treatment of chronic cholestatic liver diseases. It has cytoprotective, anti-apoptotic, membrane stabilizing, anti-oxidative and immunomodulatory effects. Prolonged administration of ursodeoxycholic acid in patients with primary biliary cirrhosis (PBC) is associated with survival benefit and a delaying of liver transplantation.