The present study examined the effect of a methanol extract of Evodiae Fructus on the blood pressure in spontaneously hypertensive rats (SHR). The systolic blood pressure was measured after rats were pretreated with phentolamine, propranolol, or $N_{omega}$-nitro-$_{L}$-arginine methyl ester(NAME) and subsequently received methanol extract of Evodiae Fructus. In SHR, intraperitoneal administration of methanol extract of Evodiae Fructus (0.5 mg/kg) produced antihypertensive effect that lasted for at least 4 hours. Antihypertensive effect of Evodiae Fructus was more stronger than that with $alpha$-adrenergic receptor antagonist phentolamine and was not affected by $eta$-adrenergic receptor antagonist propranolol. The antihypertensive effect of Evodiae Fructus was abolished by pretreatment of NAME. Our findings suggest Evodiae Fructus has an hypertensive effect, which may be mediated through nitric oxide synthesis.s.