The background against which the proposal was made had been developed from the combined information of the Veterans Administration Cooperative Study and the Hypertension Detection and Follow-up Study. Data from both these studies clearly established the importance of reducing sodium content by means of diuretic administration as a mainstay of the treatment of elevated blood pressure. The risks of the lifetime of treatment were undefined, but the cost of indefinite treatment of high blood pressure was sufficiently high to stimulate careful examination of alternative modes of management of such patients. The demonstrations by Parijs and others that moderate reduction in sodium intake led to improved management of hypertension and data suggesting that increased potassium intake may enhance this blood pressure lowering effect associated with sodium restriction was cited by the investigators as a basis for the trial. Any additional data regarding modest sodium restriction and potassium ingestion would have impact on utilizing such therapy in preventing hypertension and as adjunctive therapy.