AIH is a chronic liver disease of unknown aetiology which can affect patients of all age, sex, and race, characterized by interface hepatitis, hypergammaglobulinaemia mostly of the IgG class and circulating autoantibodies. Two types of AIH (type 1 and type 2) have been recognized based on serological markers. AIH has a heterogeneous and fluctuating nature, leading to marked variability in its clinical manifestations and it affects predominantly women and may present as acute hepatitis, chronic hepatitis, or well-established cirrhosis. Corticosteroid therapy is effective for all forms of AIH. Prednisone (or prednisolone) alone or a lower dose in combination with azathioprine induce clinical, laboratory and histological remission in 80% of patients within 3 years.