Autoimmune hepatitis (AIH) is a chronic inflammatoryconditionofthelivercharacterized by a complex interaction among genetic factors, immune response to antigens present in hepatocytes, and immune regulation alterations. Its distribution is global and there is a female predominance. AIH is divided into 2 groups, depending on the type of serum autoantibodies detected. The most common presentation is acute hepatitis (40%), with nonspecific symptoms, high aminotransferase levels,andhypergammaglobulinemia.Standard treatment consists of the administration of immunosuppressive drugs. It is a complex condition, often difficult to diagnose. If not managed adequately, the 5-year mortality rate may reach 75%.