Fatty liver is a condition that excessive fat accumulates in the liver cells, and its content exceeds 10% by weight of the liver. Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease that is closely related to metabolic diseases such as diabetes, hypertension, hyperlipidemia and obesity. Its characteristic is very similar to that of alcoholic fatty liver, but it occurs in people with little or no alcohol consumption. In developed countries, non-alcoholic fatty liver disease has become one of the most common chronic liver diseases which about 20% of the population are affected.