Abnormal alanine aminotransferase (AAT) is caused by certain damage to liver cells, which results in cell membrane damage, cell necrosis, cell division and cell decomposition, leading to abnormal AAT in the blood, which may be due to the following reasons: 1) Suffering from liver diseases, commonly found in chronic and acute viral hepatitis, fatty liver, alcoholic liver, drug-induced hepatitis, hepatocellular carcinoma and cirrhosis. 2) Hepatitis B or A may cause abdominal pain, loss of appetite, jaundice, nausea, vomiting, and other symptoms. Hepatitis B or A will have symptoms such as abdominal pain, loss of appetite, jaundice, as well as nausea and vomiting. Dermatomyositis, pulmonary infarction, muscular dystrophy, or shock may cause abnormal ALT symptoms. Since this condition can be caused by a variety of reasons, it is recommended to go to the hospital in time for diagnosis and subsequent treatment.