Thirty-two patients with chronic hepatitis who were positive for hepatitis C virus (HCV) RNA by polymerase chain reaction and had antibody to HCV (anti-HCV), were enrolled in this study. Twenty of them were also positive for antibody to the GOR epitope (anti-GOR). Sixteen of the enrolled patients were treated with human lymphoblastoid interferon for six months. Treatment was initiated with 3 million units of interferon daily for 2 weeks, followed by 3 million units three times a week for 6 weeks and 1.5 million units three times a week for 16 weeks. The efficacy of therapy was assessed by comparison with the results in 16 untreated patients. Aminotransferase values, titre of anti-HCV and anti-GOR antibodies showed significant decreases throughout the therapy compared with baseline levels and the untreated patients. After a 3 month follow-up, nine treated patients (56.3%) had normal aminotransferase activities and six of them eliminated HCV RNA from their sera (37.5%). Three of these six patients became negative for both anti-HCV and anti-GOR antibodies (18.8%). None of the untreated control patients had normal aminotransferase activities or became negative for HCV markers. The present study suggests that human lymphoblastoid interferon can control the disease activity and eliminate hepatitis C virus from patients with chronic hepatitis C.