Beta adrenergic blockade reduces utilitarian judgement

► We investigated the role of noradrenergic transmission in moral decision-making. ► The beta-adrenoceptor antagonist propranolol affected responses to moral dilemmas. ► Propranolol reduced the willingness to endorse utilitarian solutions involving harm. ► Propranolol also reduced heart rate and response times, and increased decisiveness. ► Blockade of noradrenergic arousal appears to increase aversion to harming others.