Diuretics, also known as water pills, are medications that act on the kidneys to increase the urge for urination, thus reducing the amount of sodium and fluid circulating throughout the body and blood volume, resulting in lower blood pressure. When suffering from mild hypertension, diuretics alone are often effective. Diuretics also help the blood vessel walls relax, improving blood circulation. There are three types of diuretics: thiazide, loop, and potassium-sparing, and The Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure also recommend individuals try thiazide diuretics first. Some of the most commonly prescribed diuretics include thiazide, bumetanide, chlorthalidone, metolazone, and torsemide. Since these drugs can reduce potassium levels, it's recommended for patients to consume these medications with a potassium-rich food, such as a banana.