Abstract: The present paper describes the effect of extractum of root Pueraria pseudo-hirsuta (Erpph) on the β-adrenergic receptor of various tissues of animals. The results showed that this extract had potent β-adrenergic receptor blocking effects. There is evidence that its blocking action on β₁-receptors is stronger than on β₂-receptors.It was found that at the dosage of 0.5～5 mg/ml or 750 mg/kg Erpph could antagonize the heart excitation induced by isoproterenol (0.17～1.7μg/ml or 10 μg/kg) in vivo and in vitro respectively. Erpph was also found to block the depressor reaction of the vessels by injection of isoproterenol (10/μg/kg) and adrenalin (10μg/kg) but it has no effect on the pressor reaction to nor-adrenalin (10 μg/kg). On the other hand, Erpph (750 mg/kg)was shown to decrease the resting heart rate and blood pressure (average 43.7% or average 40±6 mmHg, respectively). These facts form a theoretical bssis for using Erpph in angina pectoris, arrhythmia and hypertension.By comparing the effect of this extractum (750 mg/kg) and practolol (0.1 mg/kg) it was also found that they had almost the same β-adrenergic blocking effect, but the former was stronger to depress the blood pressure and the latter was stronger to depress the heart rateFrom these studies, it is concluded that Erpph is a potent and safe β-blocker.