Surgical restoration of bile flow in patients with extrahepatic biliary atresia (EHBA) results in the disappearance of clinical cholestasis in about 30% of cases. It is suggested that early postoperative administration of phenobarbital (PB) or cholestyramine (Ch) may improve this percentage. Eighty patients were randomly divided into three subgroups comprising 27 who were treated with Ch (4 g/d), 27 who were given PB (7.5 to 10 mg/kg/d) during the first 3 postoperative months and 26 untreated patients, who served as controls. Cholestasis was observed to disappear in 38 (group I) patients and to persist in 42 (group II) patients, as judged from their total blood bilirubin levels, the conjugated/total bilirubin ratio, measurements of cholesterol, bile acids and alkaline phosphatase, and of Rose Bengal fecal excretion. Neither Ch nor PB significantly improved the degree or duration of cholestasis in either group.