Fatty liver develops because of excessive fat infiltration in the liver, on the one hand because of excessive fat intake, and on the other hand because of a weakened function of metabolizing fats and oils, resulting in the accumulation of fats and oils in the liver. In view of these two factors, the patient may have eaten too much fatty food or food containing more sugar, resulting in excessive intake of fats and oils, or lack of physical exercise, because calories are not consumed, fats and oils or sugar can not be metabolized, and accumulate in the liver to form a fatty liver. Some patients may be fat and this kind of fatty liver is also very common, and some people, although not fat, are relatively thin and also prone to fatty liver, which may be related to the patient’s congenital metabolic function problems, in addition to particularly thin may also appear malnutrition. Therefore, the causes of fatty liver are mainly twofold, excessive fat intake and poor metabolic function of the patient.