We conducted a randomized, double-blind clinical trial of atenolol as compared with placebo in the treatment of patients hospitalized with the alcohol withdrawal syndrome. In addition to receiving customary therapy, 61 patients were randomly assigned to receive atenolol, and 59 to receive placebo. Outcome was assessed daily by the measurement of nine features in three categories: vital signs, clinical signs (e.g., tremor), and behavioral signs (e.g., agitation and anxiety). Compared with placebo patients, atenolol patients had a significant reduction in the mean length of hospital stay (four as compared with five days, P less than 0.02). On each treatment day, significantly fewer patients receiving atenolol required concomitant benzodiazepines, and patients receiving placebo required a significantly higher mean daily dose of benzodiazepines. Among patients who had withdrawal symptoms at base line, vital signs became normal more rapidly in the patients receiving atenolol, and their abnormal behavior and clinical characteristics also resolved more rapidly. We conclude that atenolol is helpful in the treatment of patients with the alcohol withdrawal syndrome.