Diarrhea that develops after cholecystectomy may be due to increased amounts of bile acids presented to the large bowel, a "cholerheic enteropathy." We have studied eight patients to determine the cause for chronic diarrhea after cholecystectomy and found no abnormality other than elevated bile acids in the stool of six of them. All patients with bile acid malabsorption had daily stool weights greater than 200 g and total fecal bile acids three to ten times greater than normal. Patients responded dramatically to treatment with cholestyramine resin.