Hypokalemia induced by the use of diuretics is common. Those at risk include the elderly, women, patients with edematous states, and patients in whom higher doses and/or the more potent agents are used. Prevention should include a low-salt diet rich in potassium, magnesium, and chloride (either through foods enriched with these elements or through potassium chloride supplements) and use of low doses of short-acting diuretics in the treatment of mild to moderate hypertension. The subgroup of hypertensive patients in whom hypokalemia develops despite these recommendations may benefit from a change to the potassium-sparing diuretic spironolactone or substitution of diuretics with alternative first-line drugs.