There are many causes of liver function damage, and the clinical manifestations are sometimes not obvious specificity, which can be manifested in the following aspects: 1. digestive function: resulting in loss of appetite, aversion to grease, nausea, vomiting, abdominal discharge or constipation, etc. 2. liver cell damage: resulting in increased serum transaminases and other enzymes, while cholinesterase decreases, which can lead to weakness, easy tiredness, sleepiness, etc. 3. abnormal bile pigment metabolism: can lead to jaundice, the main symptoms appear as When jaundice deepens, urine, sputum, tears and sweat are also yellow, saliva is generally not discolored. 4, abnormal synthesis of coagulation factors: can cause bleeding gums, nasal bleeding and other bleeding tendencies; 5, abnormal metabolism of vitamins: the lack of various vitamins cause rough skin, inflammation of the lips and tongue, swelling, skin bleeding, osteoporosis, etc. 6, other symptoms: symptoms of poor liver function are dry mouth The symptoms of poor liver function include dry mouth, dry or loose stools, yellow urine, or low fever, dizziness and tinnitus, and a shriveled and yellowish complexion. There are many causes of liver function damage, the most common in China is hepatitis B virus infection, followed by hepatitis C virus infection, alcoholic liver damage, autoimmune liver damage, fatty liver, EB, cytomegalovirus infection, etc., and some unexplained liver function damage. Usually the liver function is checked and the increase of glutamic and glutamic aminotransferase by more than 2 times is clinically significant and further examination is needed. Mild liver function impairment can be improved and reversed after removing the causative factors, but prolonged liver function impairment can lead to cirrhosis, thus entering an irreversible stage.