Hepatitis B virus (HBV) is a serious cause of morbidity and mortality in hepatitis B surface (HBsAg) antigen-positive patients treated with chemotherapy. Because the hepatitis is related to HBV virological reactivation, application of effective antiviral therapy, such as Lamivudine, has been attempted. Despite the use of these antiviral agents at the time of clinical hepatitis, some HBsAg-positive patients still develop hepatic failure and die. We used the Molecular Adsorbent Recirculating System (MARS) (MARS Monitor; Teraklin AG, Rostock, Germany) to treat 5 HBsAg-positive lymphoma patients with acute hepatic failure due to chemotherapy despite lamivudine treatment. Before and after each treatment we monitored the parameters of neurological status (EEG, cerebral CT and Glasgow coma score), hemodynamic parameters, acid-base equilibrium and blood gases as well as hepatic and renal function. The inclusion criteria were these of the King's College Hospital. Statistical analysis by Student t method showed significant results (P < .01). Three of 5 patients are alive without signs of reactivation of viral or hematological diseases at 1 year follow-up. The 2 patients died because MARS treatment was started too late, with Glascow coma score grade IV, hemodynamic instability, and mechanical ventilator assistance. Despite the limited number of cases, we believe that MARS can be applied to patients with a high tolerance and yield good results, but the treatment has to start at the first signs of hepatic failure.