Cholestyramine exerted a beneficial effect on the course of a patient with sclerosing cholangitis associated with ulcerative proctitis. Over a 6.5-yr period, discontinuation of cholestyramine resulted in episodes of RUQ pain and/or appearance of abnormalities in liver tests. Readministration of the resin was followed by disappearance of symptoms and normalization of test resuls. The mechanism of the beneficial effect of cholestyramine was not elucidated.