Non-alcoholic fatty liver disease is the most common cause of raised liver enzymes in the developed world. It is a spectrum of disease, ranging from benign simple fatty liver disease
(steatosis) to non-alcoholic steatohepatitis. Non-alcoholic fatty liver disease is associated with fibrosis and may eventually progress to cirrhosis. It is histologically indistinguishable from alcohol-related liver disease and also accounts for a substantial number of cases that are misdiagnosed as cryptogenic cirrhosis.3 It is an increasingly recognised form of liver disease and affects all age groups, including older people. We discuss the causes, clinical features, diagnosis, and management of non-alcoholic fatty liver disease and steatohepatitis.