In heavy drinkers with clinical evidence of liver disease, routine investigations should exclude the possibility of other chronic liver diseases of non-alcoholic aetiology requiring specific therapy--these include chronic viral hepatitis, autoimmune diseases of the liver, Wilson's disease and genetic haemochromatosis. If abnormalities in liver biochemistry persist despite abstinence, or if the diagnosis of alcoholic liver disease is in doubt, a liver biopsy should be carried out. Studies evaluating the role of liver biopsy in alcoholic liver disease suggest that without histological confirmation the diagnosis will be inaccurate in 10-20% of patients. Serum biochemistry and the currently available imaging modalities have severe limitations in determining the relative contributions of fatty liver, alcoholic hepatitis and cirrhosis to the overall picture in alcoholic liver disease. Histological examination is therefore of additional value in determining the prognosis, which is worst in patients with a combination of alcoholic hepatitis and cirrhosis. There are a number of indices available, based on clinical and laboratory information, for evaluating the short-term prognosis, but these can only be used with accuracy if the histological pattern of damage has initially been evaluated.