This study was aiming to explore the antihypertensive activity of two medicinal plants namely (Nigella Sativa and citrus sinensis), some drugs and chemical compounds namely (astemizole, magnesium phosphate) in animal model of induced hypertension. Two well known antihypertensive drugs namely (atenolol and furosemide) have been used too, for comparison with the other tested agents. In this study sixty-six local domestic rabbits of both sexes weighing 1000-1200 gm have been used. For the purpose of induction of hypertension, they were divided into two main groups (group one) and (group two). In (group one) hypertension has been induced by using dexamethasone and hypertonic saline injection and the agents applied to this group were atenolol, furosemide. alcohol, Nigella Sativa and Citrus sinensis, whereas in (group two) phenylephrine injection was used to induce hypertension and the agents applied to this group were atenolol. furosemide, astimazole, magnesium phosphate. Normal saline was used as a control and alcohol was used to exclude its effect on blood pressure In addition to measuring the systolic and diastolic blood pressure, other parameters have been taken into consideration namely, the heart rate. blood flow and urine output in order to predict the possible mechanisms through which the tested agents affect blood pressure and to have an overall outlook on different actions of them. It has been found that the aqueous extract of Nigella Sativa was significantly effective in lowering both systolic and diastolic blood pressure when given at a dose of 1 mg/Kg (p<0.05). the aqueous extract of nigella was as effective as furosemide in lowering the diastolic blood pressure, but it was less effective than furosemide in lowering systolic blood pressure. It was also less effective than atenolol in lowering both systoic and diastolic blood pressures. The alcoholic extract of Citrus Sinensis has been found to be significantly effective in lowering both systolic and diastolic blood pressure at a dose of Img/Kg (p<0.05). The alcoholic extract of Citrus Sinensis was more effective than furosemide in lowering diastolic blood pressure, while it was equal to it in lowering systolic blood pressure on the other hand; the alcoholic extract of Citrus Sinensis was less effective than atenolol in lowering systolic and diastolic blood pressures. Magnesium phosohate was found to be significantly effective in lowering both systolic and diastolic blood pressure at a dose of 0.5 mg/Kg (p<0.05).while furosemide and atenolol were not under the conditions of group two. Lastly, astemizole had no significant effect on blood pressure, but it has been found significantly effective in decreasing heart rate and increasing urine output.