Primary sclerosing cholangitis is a cholestatic liver disease characterized by inflammation and fibrosis of the biliary tract. The cause of the disease is unknown, and no effective medical treatment exists. In this study, 12 patients received a combination of low-dose prednisone (10 mg/day) and colchicine (0.6 mg bid). Their course was compared with that of a group of concurrent historical controls. At 6 and 12 months, there was significantly more improvement in liver test results over baseline values in patients receiving prednisone and colchicine than in the untreated controls. At 24 months, however, no significant differences in biochemical tests were appreciated between treated and untreated patients. Analysis of serial liver biopsies showed no differences in histologic change in the two groups. During the 2 yr of follow-up, there were two deaths in the control group but none in the treated group. Four untreated patients developed ascites; gastrointestinal bleeding developed in three untreated patients, one of whom developed ascites. In contrast, in the treated group, ascites and bleeding developed in only one patient. We conclude that the combination of colchicine and prednisone does not retard histologic progression or progression of standard liver tests after 2 yr of therapy. There is a trend toward less clinical deterioration and improved survival after 2 yr of treatment. On the basis of these findings, we would not advocate empiric use of these drugs for patients with primary sclerosing cholangitis, but suggest that, if they are to be used at all in PSC, they be evaluated in a controlled clinical trial as treatment for this as yet incurable disease.