Olive tree leaves have been widely used in traditional medicine for its antioxidant, antihypertensive, hypoglycemic, hypocholesterolemic and cardioprotective activity. A clinical study was conducted to evaluate the antihypertensive effect of olive leaves herbal tea (50 g of dried and ground leaves in 250 ml of warm water/twice daily for 28 weeks) in type 2 diabetic patients (n=31, 13 women and 18 men) diagnosed with prehypertension.