(S)-(-)-Propranolol hydrochloride is a β-adrenergic receptor antagonist with log Kd?values of -8.16, -9.08, and -6.93 for β1, β2, and β3, respectively. (S)-(-)-Propranolol hydrochloride the active enantiomer of propranolol and can be s used for study of hypertension, pheochromocytoma, myocardial infarction, cardiac arrhythmias, angina pectoris, and hypertrophic cardiomyopathy.