Midol is an over-the-counter medication designed to relieve multiple menstrual symptoms quickly. It treats cramps, bloating, water-weight gain, headaches, backaches and fatigue. It typically contains Acetaminophen (pain reliever), caffeine (diuretic) and pyrilamine maleate (antihistamine). Midol's generally taken every six hours, not exceeding six caplets a day. Read directions for appropriate dosage.