This study was Investigated to prove the effect of Gamidojeok-san (Jiaweidaochi-san) on the hypertension. After administer Gamidojeok-san (Jiaweidaochi-san) extract to SHR(Spontaneous Hypertensive Rat) for 5 weeks, we examined changes of blood pressure, pulse rate, aldosterone and catecholamine in serum. Results : Following results were obtained; Gamidojeok-san(Jiaweidaochi-san) showed significant antihypertensive effect. Gamidojeok-san(Jiaweidaochi-san) decreased pulse rate but insignificant. Gamidojeok-san(Jiaweidaochi-san) showed a significant decrease in the aldosterone. Gamidojeok-san(Jiaweidaochi-san) was ineffective on the dopamine. Gamidojeok-san(Jiaweidaochi-san) decreased the norepinephrine but insignificant. Gamidojeok-san(Jiaweidaochi-san) showed a significant decrease in the epinephrine. These results indicate that Gamidojeok-san(Jiaweidaochi-san) can be used in hypertension. Further study will be needed about the functional mechanism and etc..