The serum aminotransferase ALT is present in hepatocytes and is released from hepatocytes into the blood whenever the liver is damaged by inflammation, necrosis, or toxicity. Therefore, disorders of the liver itself, including fatty liver, especially all types of viral hepatitis, hepatic cirrhosis, hepatic abscess, hepatic tuberculosis, hepatocellular carcinoma, and hepatomegaly can cause ALT elevation to varying degrees. Biliary tract, gallbladder and pancreatic diseases, and biliary obstruction can also elevate ALT. Clinically common are cholecystitis, biliary roundworm. Hepatobiliary stones, gallbladder and bile duct tumors, peripelvic carcinoma, congenital choledocholithiasis, acute and chronic pancreatitis, pancreatic head cancer and hemorrhagic necrotizing pancreatitis. Pharmacological or toxic liver damage, as well as drug allergy can cause ALT elevation, often accompanied by cholestatic jaundice and hepatocellular damage. Clinically used antibiotics such as tetracycline, vancomycin, ashwagandha toxin, sulfadiazine; anti-tuberculosis drugs such as isoniazid, sodium para-aminosalicylate, rifampicin, pyrazinamide; antipyretic and analgesic drugs such as paracetamol, finasteride; sleeping anesthesia drugs such as chlorpromazine, lisdexamfetamine and Valium; anti-rheumatic drugs; anticancer drugs; cardiovascular drugs such as methyldopa; hormones such as methyltestosterone, nandrolone diphenylpropionate, and nandrolone phenylacetate; oral contraceptives such as compound norethisterone and norethisterone. Contraceptive compound norethindrone tablets (contraceptive No. 1), megestrol, ethinyl estradiol; anthelmintic blood 846, adiponectin, arsine carbazate, antimony potassium tartrate; Chinese medicine zebra mussel, cangzhi, strychnine, grass wool, yellow herbs, and so on. It has been reported that the use of the drug 12-48 hours will cause ALT rise, 4-1O days can reach the peak, and after stopping the drug in time, most of them will return to normal within 3 weeks. In addition to the liver, other tissues in the body, such as the heart, kidney, lungs, brain, testes and muscles also contain this enzyme. Therefore, when myocarditis, pyelonephritis, lobar pneumonia, tuberculosis, cholecystitis, leptospirosis, influenza, measles, schistosomiasis, systemic lupus erythematosus, hyperthyroidism, diabetes, malignant reticulocytosis, heart failure, rheumatic fever. Elevated ALT is also seen in peptic ulcer, acute and chronic gastroenteritis and uremia. Elevated aminotransferases can also be seen in normal pregnancy, gestational toxicosis, and acute fatty liver of pregnancy. In addition, strenuous exercise can also be seen ALT elevation. It can be seen that the causes of elevated serum ALT are multifaceted, and it is necessary to take a detailed history, do the necessary physical and chemical examination, and can be combined with the specific diagnosis of hepatitis A, B, C, D, E and liver biopsy to help diagnosis.