Alcohol withdrawal is associated with a decrease in gamma-aminobutyric acid neurotransmission. This explains the efficacy of benzodiazepines. However, an increase in adrenergic activity may also play a part in alcohol withdrawal symptoms, suggesting a potential efficacy of beta-blocking drugs. A double-blind comparative study of propranolol and diazepam was carried out in 28 patients suffering from moderate uncomplicated alcohol withdrawal. Patients were treated for 15 days with either 75 mg of propranolol or 30 mg of diazepam. The results show that both drugs at the dosages used are equipotent in reducing physical withdrawal symptoms and anxiety symptoms. This suggests that most likely the central as well as the peripheral effects determine the clinical usefulness of propranolol in the management of alcohol withdrawal. However, propranolol is ineffective in preventing major motor seizures, suggesting that different neurobiological mechanisms underlie the alcohol withdrawal symptoms.