The alcohol withdrawal syndrome is characterised by symptoms such as anxiety, insomnia, anorexia, nausea, tremor, sweating and disturbances in coordination. These symptoms tend to occur within 6 to 12 hours of alcohol-dependent patients stopping or reducing their alcohol intake. Less frequently, convulsions, hallucinosis and delirium tremens can occur. Delirium tremens (disturbed orientation, visual and auditory hallucinations, paranoid ideation and tremulousness) is the most serious complication of alcohol withdrawal and occurs in up to 5% of patients withdrawing from alcohol. If it is severe or poorly treated, death can occur. In the UK some clinicians use chlormethiazole while others favour chlordiazepoxide. This article will examine and compare the use of these two drugs.