Diuretic drugs and low-sodium diets are effective in control of hypertension. They seem to have a similar mechanism of action that is dependent on their ability initially to produce a negative salt and water balance and, during long-term treatment, to prevent sodium retention. This effect on body sodium and water stores produces both short-term and long-term hemodynamic adjustments that account for the arterial blood pressure reduction. There is a wide variety of diuretic drugs available with differing potencies and renal sites of action. All, however, have similar antihypertensive potential when given in equal diuretic dosages. Dietary sodium restriction is equally effective in lowering arterial blood pressure, but its usefulness is sharply limited by cultural dietary habits.