The effectiveness and practicality of low sodium diets are tested in groups of in- and outpatients. The data indicate that roughly one-fourth with severe essential hypertension can respond favorably to prolonged restriction of sodium intake to less than 0.5 Gm. daily. The rice diet is found to be in effect a simple low sodium diet. Under the conditions of outpatient practice, low sodium dietotherapy is usually impractical and must be controlled by frequent analyses of urinary sodium.