Dissolution of cholesterol gallstones by ursodeoxycholic acid.

44 patients with radiolucent gallstones in gallbladders visible on cholecystography were randomly alloted to three treatment groups: ursodeoxycholic acid (600 mg/day), ursodeoxycholic acid (150 mg/day), a placebo. At the end of six months' treatment, cholecystograms of all the patients were interpreted by radiologists who were not aware of the treatment. Dissolution of gallstones occurred in 8 (26%) of the 31 patients treated with ursodeoxycholic acid, but not in the placebo group. Ursodeoxycholic acid had no hepatotoxicity, as assessed by standard liver-function tests. These results indicate that ursodeoxycholic acid, the 7beta epimer of chenodeoxycholic acid, is effective in the dissolution of cholesterol gallstones.