Fatty liver is a common clinical phenomenon, not a separate disease. Fatty liver is a lesion caused by excessive accumulation of fat in liver cells due to various reasons. Normal intrahepatic fat accounts for 3% to 5% of the wet weight of the liver, of which 2/3 are phospholipids and 1/3 are triglycerides, cholesterol, and fatty acids. Due to various reasons, such as: increased supply of exogenous fatty acids, intrahepatic fatty acid synthesis, decreased oxidation of hepatic fatty acids, low-density lipoprotein clearance of intrahepatic triglyceride obstacles, etc., so that the hepatic fat metabolism dysfunction, resulting in a dynamic imbalance of lipids, excessive fat accumulation in the hepatocytes, if the accumulated fat (mainly triglyceride) content of more than 5% of the wet weight of the liver, or in the histologic If the content of accumulated fat (mainly triglycerides) exceeds 5% of the wet weight of the liver, or if more than 50% of the liver cells are histologically fatty, it is called fatty liver. There are many causes of fatty liver, the common causes are: 1, excessive alcohol consumption; 2, diet too oily, too sweet, nutritional imbalance; 3, medication fatty liver; 4, diabetes mellitus, Cushing’s syndrome, thyroid disease; 5, some special circumstances, such as pregnancy, small bowel resection using parenteral nutrition, and so on. Those who are obese (usually more than 10% or more of ideal body weight) alcoholics; diabetic patients; lose weight too fast and long-term use of drugs with liver damage are more likely to develop fatty liver. In mild cases of fatty liver, there are no clinical symptoms and they can be easily overlooked. Some only have fatigue, and most people with fatty liver are fat, so it is more difficult to find minor symptoms. In severe cases, there may be manifestations similar to chronic hepatitis, such as loss of appetite, fatigue, nausea, vomiting, weight loss, vague pain in the liver area or the right upper abdomen, etc. The mildly enlarged liver may have symptoms such as a lack of appetite, fatigue, nausea and vomiting. Mildly enlarged liver may have tenderness, slightly tough texture, blunt edge, smooth surface, and a few patients may have splenomegaly and liver palms. Severe fatty liver can eventually develop into cirrhosis, so it needs to be actively controlled. For asymptomatic mild simple fatty liver, it can be relieved and recovered by removing the causes and triggering factors, strengthening dietary control and enhancing exercise. For moderate or severe fatty liver with symptoms such as elevated aminotransferases, active treatment should be carried out along with elimination of causes, diet control and exercise. According to the condition, liver protection, fat removal and anti-fibrosis treatments should be given to actively control liver inflammation, get rid of intrahepatic fat and prevent liver cell necrosis and fibrosis. Early diagnosis and early treatment can effectively control the further development of fatty liver and reverse the condition.