The prevalence of non-alcoholic fatty liver disease (NAFLD), the most common type of liver disease, is increasing worldwide and has been recognized as a public health problem in Taiwan. NAFLD encompasses simple steatosis to more progressive steatosis with associated hepatitis, fibrosis, cirrhosis, and in some cases, hepatocellular carcinoma. Since NAFLD is strongly associated with metabolic syndrome and type 2 diabetes mellitus, the patients may have increased risk of complications or progressing to advanced fibrosis and nonalcoholic steatohepatitis. In this review, we focus on the epidemiology, risk factors, diagnosis, and medications, and how NAFLD may be improved.