Iran is rich in medicinally important plants and has an ancient herbal treatment methods. Our work is based on the study of some indigenous plants which show inhibitory effect of glucose utilization, and are in use as hypoglycemic agent in traditional system of medicine. Gymnema sylvestre, Momordica charantia and Eugenia jumbolana have been shown to possess hypoglycemic activity of varying degree. After preparation of glucose solutions and mentioned herbal aqueous extracts, quantative measurement of glucose was done by o-toluidine and glucose oxidase methods in various PH. The results in three different media revealed that, hypoglycemic activity is more prominent in neutral and basic media as compared to acidic medium.