Aminotransferases play an extremely important role in amino acid metabolism and the interconversion of protein, fat and sugar. When hepatitis occurs, hepatocytes are destroyed or cell membrane permeability is increased, and ALT can penetrate into the blood, causing a significant increase in the activity of the enzyme. However, it should be pointed out that not all ALT elevations are due to hepatitis, and there are many causes other than hepatitis that can also cause ALT elevations or significant elevations. 1, infection: certain bacterial, parasitic infections can increase ALT; 2, poisoning: endogenous toxic substances including autotoxins absorbed by the small intestine, certain pathological processes (such as tumors, infarction, burns, shock, inflammation) when the tissue breakdown products; exogenous toxins including organic toxins such as chloroform, bacterial toxins, inorganic toxins such as yellow phosphorus can also increase ALT; 3, nutritional deficiencies: low protein diet 4, blood circulation disorders: such as heart failure, small packet filling, liver stasis, long-term ALT can be elevated; 5, biliary obstruction: extrahepatic biliary obstruction such as: gallstones, tumors, inflammation, parasites, etc.; intrahepatic obstruction: cirrhosis, etc., can cause hepatocyte necrosis or increased permeability, so that 6, tumors: liver and biliary system tumors can cause hepatocyte destruction or biliary obstruction, resulting in ALT elevation; 7, material metabolism disorders and endocrine dysfunction: such as hyperalgesia, hyperthyroidism, hepatomegaly, etc. can cause liver damage and ALT elevation; 8, certain drugs and chemical toxins: such as rifampin, phenobarbital, arsenic, antimony, carbon tetrachloride, etc. can Certain drugs and chemical poisons: such as rifampin, phenobarbital, arsenic, antimony, carbon tetrachloride, etc. can cause different degrees of liver damage, and ALT can be increased to different degrees; 9. Therefore, ALT is not a specific indicator for the diagnosis of hepatitis, but an important indicator to assist in the diagnosis of hepatitis. When someone has an elevated ALT, it should be combined with clinical symptoms and signs, or supplemented with other tests and laboratory tests to make a correct diagnosis. When a person has an elevated ALT test, it should be combined with clinical symptoms and signs, or supplemented with other tests and labs to make a correct diagnosis.