Clinically, fatty liver is broadly categorized into four grades according to its severity, i.e., simple fatty liver, steatohepatitis, fatty liver fibrosis and fatty liver cirrhosis. Simple fatty liver is a fatty liver in which liver function remains normal, and steatohepatitis is a fatty liver in which liver function is abnormal, indicating that the fatty liver has reached a state of liver cell damage. Steatohepatitis fibrosa is recurrent or persistent abnormal liver function, where a large number of hepatocytes are damaged and the liver develops hepatic fibrosis. Steatohepatocirrhosis is the ultimate state after significant exacerbation of hepatic fibrosis, and the development of cirrhosis indicates that an irreversible and severe state has been reached. Fatty cirrhosis becomes cancerous, i.e., hepatocellular carcinoma, and is no longer classified within the grade of fatty liver.