Ursodiol (trade names Actigall, Ursofalk, Urso Forte) is a bile acid found in large quantities in bear bile; it also occurs naturally in human bile in smaller quantities. The commercial drug is synthesized, it is not derived from animals. It reduces cholesterol absorption and is used to dissolve gallstones in patients who want an alternative to surgery, as well as the recommeded treatment for Primary biliary cirrhosis and other cholestatic diseases. The drug is very expensive, however, and if the patient stops taking it, the gallstones recur. For these reasons, it has not supplanted surgical treatment by cholecystectomy.