The therapy concept is based on a theory of the immunocorrective effect of orally administered natural human interferon alpha in low doses (leuHuIFN alpha (ldou)), manifolded by the logistic amplification system seated in the oral cavity. Fourteen randomly selected patients with chronic active type B hepatitis, aged 7-59 years, were assigned to treatment. All the patients had been treated for several months to several years with steroids, with no beneficial effect--clinical and biochemical symptoms of active liver disease, with histopathological progression (up to liver cirrhosis) had been permanently present. Treatment with leuHuIFN alpha (ldou) (doses: 50-100 U daily) was introduced immediately after the immunosuppression (steroids, steroids+azathioprine) discontinuation, and its influence on the course of the disease was monitored by means of hematological and biochemical tests, humoral and cellular immune response parameters, serological markers of HBV infection, HBV DNA concentration and immunohistochemical evaluation of liver biopsy specimens. The observation period ranges from 15 to 32 months. In all patients, within the first 3-6 weeks of treatment, transient deterioration of biochemical liver function tests was noted (e.g. 2-3 fold increase of ALAT), with no clinical symptoms of the disease exacerbation. The phenomenon lasted for 4-16 weeks. In all the treated patients, intensive immune system activation was seen, which lasted beyond the therapy period. Seven patients eliminated serum HBV DNA; all of them also eliminated HBeAg and seroconverted to HBeAb. Up to date, one person have lost serum HBsAg, in nine others its titre decreased significantly.