Seven carriers of the Hepatitis B surface antigen who had acquired a form of chronic hepatitis D in the recent past were treated with lymphoblastoid alpha interferon (IFN) (10 MU three times weekly for 4 months, 6 MU three times weekly for other 8 months, with a 12 month follow-up after treatment). At the beginning of the study, these patients had a chronic active hepatitis with intrahepatic hepatitis D antigen but without signs of cirrhosis. By the end of therapy, five had normal amino-transferases and no trace of HDV-RNA in the serum. In two patients the liver enzymes and viremia relapsed during follow up; biochemical and virologic remission persisted after discontinuation of therapy in the other three patients. In the early non-cirrhotic stage of chronic hepatitis D, IFN may play a more consistent therapeutic role than in the average advanced case of the disease. Cytokine should be used as soon as a diagnosis of progressive hepatitis D is reached.