Evidence is presented demonstrating the role of prostaglandins in salt metabolism and on peripheral vasodilation. A number of animal studies and observations in human hypertensive subjects suggest that the prostaglandin system plays a role in the pathogenesis of hypertension. The most striking and consistent finding over many decades of investigation is the relationship between dietary salt intake and the development of hypertension. Only a small percentage of any population develops hypertension. It is suggested that those people whose kidneys have an abnormal salt-handling capacity develop hypertension when challenged by a chronic high-salt intake. The salutary effects of diuretics or low-salt diet support this concept. Hypertension then is an expression of a renal abnormality. Prostaglandins, one of the renal salt regulating factors of the kidney, amy be involved in this abnormality. Whether there is a defect in the matabolic pathways or an unresponsiveness to normal stimuli of prostaglandins has not been determined. The use of prostaglandins in the treatment of hypertension is being explored. The demonstration that PGA1 can effectively lower blood pressure and reverse hypertensive emergencies indicates that prostaglandins probably have a broader, still unidentified role in the overall management of essential hypertension.