Secretin, a gastrointestinal hormone, has been shown to have a potent choleretic effect. Having already obtained some beneficial effects with secretin in patients with intrahepatic cholestasis, we sought to confirm its effects in a double-blind placebo-controlled study in patients with mild jaundice after acute or during chronic hepatitis, where total bilirubin level was in excess of 4.0 mg/dl for 3 days or more. Patients with primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), and familiar hyperbilirubinemia were excluded from the study. Ninety-three patients were included in this analysis, but the final evaluation covered 69 of them. No statistically significant differences were found in the reduction of serum bilirubin levels between secretin and placebo groups. As a number of patients with liver cirrhosis had been included, the subjects were subdivided into one group with cholestasis in hepatitis and one with liver cirrhosis. In the subgroup of cirrhotic patients who received secretin, serum levels of AST were significantly increased compared with the placebo group. However, since the choleretic effect of secretin is unique, further studies seem to be warranted.