Preoperative administration of gallamine was evaluated during inhalation anaesthesia with nitrous-oxide and halothane with two administrations of suxamethonium 1 mg/kg body weight, 5 min apart. Sixty healthy patients were randomly divided into three groups and preanaesthetic gallamine, 0.3, 0.4 or 0.5 mg/kg body weight, respectively was administered intravenously 3 min before induction, according to the allocation. Just before induction of anaesthesia the patients were examined for signs and symptoms of partial curarization. After induction of anaesthesia by nitrous-oxide-oxygen-halothane, suxamethonium 1 mg/kg was given intravenously. Exactly 5 min later the same dose was repeated. ECG was monitored continuously and serum potassium, Pao2 and Paco2 were measured at appropriate intervals. It was found that none of the examined doses of gallamine gave any reliable protection against serious bradyarrhythmias after repeated doses of suxamethonium. Furthermore the higher doses of gallamine caused an unacceptably high frequency of patients with tachycardia and signs and symptoms of partial curarization.