Acute viral hepatisits may be asymptomatic, symtomatic but anicteric, or a classical icteric hepatitis; rarely it is very severe and may be fatal. Different types of illness may be causes by the various hepatitis viruses. This does not help precise diagnosis, which is based on serological tests. This paper describes hepatitis seen with the A, B, C, D and E, viruses, and also smeof the unusual complications which have been recognized.Serological tests allow precise diagnosis of acute hepatitis A and B and should be used more widely, because viral hepatitis is oftendiagnosed when jaundice is caused by other conditions. They also allow diagnosis when viral hepatitis has an atypical presentation, and is thus not considered as the cause of the liver disease. Negative tests suggest the need for further investigation. © 1990 The British Council 1990.