Melilotus officinalis (L.) Pallas., is used traditionally to treat hypertension and chronic venous insufficiency. The high prevalence of hypertension and the side effects of antihypertensive drugs potentiate us to evaluate Melilotus officinalis. The hypotensive effect of Melilotus officinalis butanolic fraction (MOBF) was investigated in anaesthetized normotensive rats. The doses of 60, 80 and 100 mg/kg, i.v., produced a significant (P<0.05) decrease in blood pressure. The statistically non significant reduction in blood pressure was showed by 20 and 40 mg/kg, i.v. These results suggest that Melilotus officinalis exhibited hypotensive effect in normotensive rats. However further evaluation of compound related activity is required.