Nonalcoholic steatohepatitis(NASH) is a severe form of nonalcoholic fatty liver disease(NAFLD). The causes are known to be associated with metabolic diseases such as obesity, insulin resistance type 2 diabetes, and hypercholesterolemia. Histologically, it is characterized by steatosis, hepatocellular injury, and inflammation and fibrosis of the liver parenchyma. Nonalcoholic steatohepatitis (NASH) may progress to cirrhosis and hepatocellular carcinoma(HCC) may develop even in patients without viral hepatitis, therefore there have been much interest and many researches in causation and diagnosis for nonalcoholic steatohepatitis(NASH).