Bile duct perfusion with corticosteroids is reported to improve the cholangiographic and biochemical abnormalities in some patients with primary sclerosing cholangitis. In a randomised placebo controlled trial, thirteen consecutive patients received continuous bile duct irrigation with either normal saline (1 l/day) or normal saline plus hydrocortisone (100 mg daily) via a nasobiliary tube placed in a hepatic duct at endoscopic retrograde cholangio-pancreatography. Eleven patients completed lavage for 2 weeks but no cholangiographic changes were observed in either group. Liver function tests deteriorated during lavage, but later returned to pre-treatment levels. Although bile was sterile at start of lavage, a wide range of bacteria was isolated from bile in all patients during treatment, and cholangitis with septicaemia occurred in 2 patients. We conclude that nasobiliary lavage is not beneficial in treating primary sclerosing cholangitis.