Alanine aminotransferase is mainly found in various cells, such as the liver and heart, with the highest amount present in hepatocytes. Its high level may be related to physiological reasons, liver diseases, other diseases, etc. 1. Physiological reasons: such as strenuous exercise, overwork, drinking a lot of alcohol and so on. In life, the liver can be affected and alanine aminotransferase is high. 2. Liver diseases: common ones are cirrhosis, alcoholic hepatitis, drug-induced hepatitis and so on. Due to the massive destruction of liver cells, alanine aminotransferase in liver cells is released into the blood, which is obviously high. 3. Other diseases: such as heart failure, myocarditis and other diseases. High alanine aminotransferase can also occur due to the destruction of cardiac muscle cells. When alanine aminotransferase abnormalities occur, in addition to exclude physiological causes, follow the doctor’s instructions for further relevant examinations, with the help of the doctor to clarify the causes, and targeted treatment or therapy.