Attempts were made to investigate the pharmacological actions of Euonymus japonicae Cortex which is used as a substitute of Eucommiae Cortex. Practically the influence of the alcohol extract of the bark on the blood pressure response of rabbit, was examined, and the results are as follows. 1) The intravenous injections of the alcohol extracts of the bark decreased the blood pressure of rabbits to 4.6 11.1 and 34.2 mmHg respectively. 2) The intravenous injection of 10 mg/kg of the alcohol extract after intravenous injection of atropine 4 mg/kg or that of propranolol 2 mg/kg did not give any notable change to the blood pressure. 3) The intravenous injection of 10 mg/kg of the alcohol extract slightly decreased the raised blood pressure caused by the administration of acetylcholine $10^{-8}g/kg;and;10^{-7}g/kg$.