Selected immunological, biochemical, and other viral hepatitis B (VH-B) markers were followed and analysed during "conventional" or human interferon alpha (HuIFN alpha) therapy of patients with different forms of VH-B. The immunological data obtained from "conventionally"-treated acute hepatitis B (AH-B), prolonged acute hepatitis B (AH-BP) or chronic active hepatitis B (CAH-B) patients disclosed differences unsatisfactory for comparison of the influence of HuIFN alpha therapy on changes of the immunological markers. More valuable data were obtained through continuous registration of the dynamics of selected blood markers. Partial effects on immunological parameters were seen after HuIFN alpha administration to 2 patients with developing CAH-B infection. Progression of the disease was markedly halted in these both patients after IFN treatment.