Fatty liver is most common in the following types of people: obese people, excessive alcohol drinkers, people on high-fat diets, people with little movement, people with chronic liver disease, and middle-aged and elderly endocrine patients. Obesity, excessive alcohol consumption and diabetes mellitus are the three main causes of fatty liver. The causes of large fat droplet fatty liver are: 1, nutritional: malignant malnutrition in children (forashiorkor) gastrointestinal diseases, pancreatic diseases, obesity, intestinal bypass surgery and long-term parenteral nutrition. 2, metabolic: diabetes mellitus, galactosemia, glycogen deposition disease, fructose intolerance, hepatomegaly, tyrosinemia, hyperlipidemia, no beta lipoproteinemia, Wolman’s disease, lipofuscinosis, etc. 3.Pharmacological: including ethanol poisoning, long-term application of adrenocorticotropic hormones or hepatotoxic drugs. 4.Viral infectious: including viral hepatitis C and E and other systemic viral infectious diseases. 5, insidious: among the above causes, diabetes, obesity and ethanolic fatty liver are the most common. About 60% to 90% of diabetic and obese patients can be found to have different degrees of fatty liver on liver puncture pathology. The causes of small droplet fatty liver include: acute pregnancy fatty liver, Reye’s syndrome, tetracycline fatty liver, Jamaican vomiting disease, valproate poisoning, congenital urea cycle enzyme defect, ethanol poisoning and cholesterol lipid deposition disease, etc. Among them, pregnancy fatty liver, tetracycline fatty liver and Reye’s syndrome are the most common. Several types of causes of fatty liver formation. 1, alcohol is the culprit, long-term alcohol consumption, resulting in alcohol poisoning, resulting in the reduction of fat oxidation in the liver, chronic alcoholics nearly 60% of fatty liver, 20% to 30% will eventually develop into cirrhosis. 2, long-term intake of high-fat diet or long-term eating a lot of sugar, starch and other carbohydrates, so that the liver fat synthesis too much. 3, obesity, lack of exercise, so that too much fat input in the liver. 4.Diabetes. 5.Hepatitis. 6.Acute or chronic liver damage caused by certain drugs.