After an interval of around two months from the cessation of varenicline use, the second flare emerged, as evidenced by increased serum ALT values now associated with newly increased serum autoimmune titers of antinuclear antibodies (ANAs), classifying this flare as hepatic autoimmune injury with verified causality for varenicline using the simplified autoimmune hepatitis (AIH) score. This evidence concerns the gene GPT and autoimmune hepatitis.