Patients with elevated arterial pressures and no definable cause are said to have Primary, Essential or Idiopathic hypertension. A variety of complexly interrelated systems in the body: the Central and /or the peripheral Adrenergic, Renal, Hormonal, Vascular have been implicated in the pathogenesis of Essential hypertension. Besides, a number of environmental factors also contribute to the multifactorial causation. However the exact picture is still far from clear. Pickering's view held that blood pressure was distributed as a skewed unimodal curve and Essential hypertension was therefore an arbitrarily segregated group lying in the upper part of blood pressure distribution.