To evaluate the effect of acupuncture on the hypertension, the study was done by acupuncture on bilateral Inyong(ST9) with rats which are normal and acutely increased hypertensive. The results are as follows: 1. Under the normal condition, the acupuncture on bilateral Inyong caused a quick drop of mean arterial pressure(MAP), but heart rate(HR) was not changed significantly. 2. To increase the blood pressure, acutely epinephrine was administered and it caused a increase in both MAP and HR. With acupuncture, the MAP was decreased while HR did not show a significant change. In conclusion, the acupuncture was somewhat effective in lowering the mean arterial pressure in the rat.