Currently, alpha interferon is the only recognized therapy for chronic viral hepatitis. As a result of its success in several multicenter trials, the agent was approved recently by the FDA for use in the clinical management of patients with chronic hepatitis C. FDA approval for its use in chronic hepatitis B is anticipated. Based upon this experience in nonimmunosuppressed individuals, the efficacy of alpha interferon therapy in patients who are recipients of liver allografts and are receiving chronic immunosuppression was assessed in a preliminary trial of the agent in 30 patients (13 with HBV, 11 with HCV, and 6 with hepatitis non A, non B, non C). Therapy was initiated at a dose of 3 X 10(6) units three times per week and continued for 6 months. Dose reduction in the amount of the alpha interferon administered was determined by a preestablished protocol. Nine percent of those with HCV and 18% of those with hepatitis non A, non B, non C experienced a full response to alpha interferon therapy. No full responses to alpha interferon therapy. No full responses were seen in those with HBV disease. Partial responses were common in all three groups but were most frequent in those with hepatitis non A, non B, non C and least frequent in those with HCV-related disease. This preliminary experience demonstrates the following: 1. Viral hepatitis following OLTx can be treated with alpha-2b-interferon. 2. The complications of alpha-2b-interferon therapy utilized prior to OLTx can be avoided by giving the therapy following successful OLTx. 3. The high rate of partial responses noted suggests that future studies should utilize either higher doses or longer durations of therapy or both. 4. The response rate was greatest for those having non A, non B, non C hepatitis and least for those with HCV hepatitis. 5. In this small preliminary series, no episodes of liver graft rejection could be ascribed to the use of alpha-2b-interferon in the patients so treated.