Symptoms of acute viral hepatitis during the prodromal period are non-diagnostic. Icteric periods are rare in acute hepatitis C, but frequent in patients with hepatitis A and E. Clinically, the liver is palpable in 70 to 90%, whereas the spleen is rarely augmented (5 to 10%). The various forms of acute hepatitis can not be distinguished clinically. The prognosis depends on the type of the virus (mutant?) and the immune reaction of the organism. Cases of chronic hepatitis are unknown following acute hepatitis A and E. However, 40 to 70% of patients with sporadic or posttransfusion hepatitis C develop chronic hepatitis. The chronicity rate of acute hepatitis B depends markedly on the age of patient at the time of infection. About 3 to 5% of the patients develop chronic hepatitis when infected in adult life. The chronicity rates increase markedly if patients are infected with the delta-virus (HDV-superinfection). A fulminant course of hepatitis A and E is a very rare event, except in the case of pregnancy in acute hepatitis E. Infection with HBV-mutants and HCV-infection both are associated with a higher frequency of fulminant courses. Patients with presumed fulminant hepatic failure due to sporadic HCV-infection contribute significantly to the numbers of cases of fulminant hepatitis.