The article discusses the International Autoimmune Hepatitis Group's efforts to establish standardized diagnostic criteria and response criteria for autoimmune hepatitis (AIH). The group, convened at the 1992 Biennial Meeting of the International Association for the Study of the Liver, aimed to refine the criteria for diagnosing AIH, which has been recognized for over 30 years in white subjects. The criteria were updated to address the challenges of diagnosing AIH, including the variability in symptoms, the absence of typical signs, and the presence of other autoantibodies. The panel emphasized that the absence of certain autoantibodies should not exclude a diagnosis of AIH but that female gender, liver test abnormalities, and other autoallergic conditions are important factors. The article also highlights the importance of histological findings and the need for further research to understand the relationship between AIH and hepatitis C virus (HCV) infection. The panel developed a scoring system to assist in diagnosing AIH and assessing response to therapy, emphasizing the need for ongoing reassessment of patients.The article discusses the International Autoimmune Hepatitis Group's efforts to establish standardized diagnostic criteria and response criteria for autoimmune hepatitis (AIH). The group, convened at the 1992 Biennial Meeting of the International Association for the Study of the Liver, aimed to refine the criteria for diagnosing AIH, which has been recognized for over 30 years in white subjects. The criteria were updated to address the challenges of diagnosing AIH, including the variability in symptoms, the absence of typical signs, and the presence of other autoantibodies. The panel emphasized that the absence of certain autoantibodies should not exclude a diagnosis of AIH but that female gender, liver test abnormalities, and other autoallergic conditions are important factors. The article also highlights the importance of histological findings and the need for further research to understand the relationship between AIH and hepatitis C virus (HCV) infection. The panel developed a scoring system to assist in diagnosing AIH and assessing response to therapy, emphasizing the need for ongoing reassessment of patients.