The roles of the liver include metabolism, secretion and excretion of bile, detoxification, hematopoiesis and coagulation. 1. Metabolism: It can participate in the metabolism of vitamins (vitamin A, B, C, D, etc.), hormones (sex hormones) and other important substances, and many drugs and alcohol are metabolized by the liver. Protein, fat and sugar metabolism can not be separated from the participation of the liver, most of the protein synthesized in the liver. 2. Secretion and excretion of bile: the liver is able to synthesize about 1 liter of bile in 24 hours, which is transported to the gallbladder, which then plays a role in concentrating and discharging the bile. 3. Detoxification: It can detoxify the toxic substances produced by metabolism or foreign substances in the body, and change them into more soluble or non-toxic substances, which can be discharged from the body with bile or urine. 4. Hematopoiesis and coagulation: the liver is an important hematopoietic organ during fetal period, and will be replaced by bone marrow hematopoiesis in adult; moreover, most of the coagulation factors are synthesized by the liver, and the liver can also play a role in regulating the dynamic balance of anticoagulation and coagulation. It is advisable to seek medical attention if liver function is abnormal.