Normal people generally have only one liver, only a very small number of people may have more than one liver due to congenital genetics and other reasons. The liver is extremely important to the human body and has mainly synthetic functions, bile secretion and excretion functions, metabolic functions, detoxification functions, hematopoietic functions, etc. 1. Synthetic functions: most of the amino acids in food proteins absorbed into the blood through digestion are taken up by the liver, which synthesizes albumin and many other proteins, which are then released into the blood and perform their respective protein functions. In addition, most of the coagulation factors involved in hemostasis are synthesized in the liver, which has a very strong ability to synthesize triglycerides, phospholipids and cholesterol. Therefore, when the liver is severely damaged, hypoalbuminemia, abnormal coagulation function and reduced cholesterol will occur; 2. Secretion and excretion of bile function: the liver can convert cholesterol into bile acids, which are secreted into the intestine with bile to promote lipid digestion and absorption; 3. Metabolic function: the liver is an important organ for maintaining constant blood glucose concentration, and the liver has strong glycogen synthesis and decomposition capabilities. When blood sugar rises, a large amount of synthetic glycogen can be stored in the liver, and when hungry, liver glycogen is rapidly broken down into glucose. In addition, the liver has a strong ability to decompose triglycerides and fatty acids, and is an important organ for ketone body production. In normal people who are hungry, ketone bodies can be oxidized for energy supply, which is a supplement to energy supply. But a large number of ketone bodies can cause acidosis, need to eat as soon as possible to improve and reduce the production of excessive ketone bodies; 4, detoxification function: the liver can be toxic substances or drugs in the body through biological transformation into non-toxic or less toxic waste, through the feces and urine out of the body. For example, protein metabolites blood ammonia, toxic to the body, need to synthesize urea in the liver, and then detoxified through the kidney excretion. Hormones, neurotransmitters and drug metabolites that are detrimental to the body need to be processed and transformed by the liver; 5. Hematopoietic function: The liver is the main hematopoietic organ during fetal life, and as it continues to grow, the hematopoietic function is gradually replaced by the bone marrow, but under the influence of some diseases, the hematopoietic function of the liver will be restored again. When the liver becomes diseased, it will seriously endanger the health of human body. For the sake of health, it is recommended to drink less alcohol, eat regularly and insist on exercise on a daily basis to reduce the unfavorable factors to the liver and protect it.