The treatment of chronic hepatitis C is relatively unsatisfactory and many patients have turned to unproven alternative medicines to modify the course of their illness. We report a study of a Chinese herbal medicine preparation CH-100 in the management of chronic hepatitis C. Patients with documented chronic hepatitis C were randomly allocated to receive active herbal or placebo tablets (five tablets thrice daily). Patients were followed monthly and evaluated by a Western and a traditional Chinese medical practitioner. Therapy was monitored by measurement of liver function tests, creatinine and full blood count on a monthly basis. Twenty patients in each group were well matched for age, sex, duration of illness, previous interferon therapy and alcohol intake. Active Chinese herbal medication was associated with a significant reduction in alanine aminotransferase (ALT) levels over the 6 month study period (P < 0.03). No patient cleared the virus but four normalized their ALT on treatment. Appropriately prescribed Chinese herbal medicine may have a role in the management of chronic hepatitis C and further controlled studies are indicated.