The term chronic hepatitis is used to include prolonged inflammation of the liver following an attack of acute viral hepatitis, either icteric or anicteric, or chronic active hepatitis, of unknown aetiology. We accept the Fogarty proceedings definition of chronic hepatitis as inflammation of the liver for six months or more, although the duration of the biochemical or histological abnormalities before the term chronic hepatitis has been used by different authors has varied from ten weeks to six months or even one year. The diagnosis is based on clinical, biochemical, histological and immunological findings. It is important to assess these carefully, often with serial liver biopsy, to determine the clinical course and prognosis and therefore the need for treatment in a particular patient.