Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in affluent countries. Patients with nonalcoholic steatohepatitis (NASH), a severe form of NAFLD characterized by ballooning, lobular inflammation and liver fibrosis, have increased mortality rate and risk of cardiovascular disease. Besides, some patients progress to cirrhosis and may even develop hepatocellular carcinoma. In long-term studies, up to 13% of NAFLD patients died of hepatic complications.(1)