Research shows that taking nonsteroidal anti-inflammatory drugs (NSAIDs) such as naproxen(Aleve and generic) can help with the headaches, cramping, and mood symptoms of premenstrual syndrome. One of the main ways that NSAIDs may help is by reducing inflammatory substances called prostaglandins that are thought to make that time of the month such a pain.

Although drugs marketed specifically for PMS symptoms, such as Midol and Pamprin, are big sellers, they usually cost more than generic NSAIDsand contain ingredients that you probably don’t need or want. For example, two Midol Complete caplets contain 1,000 milligrams of acetaminophen (the amount in two Tylenol Extra Strength pills), 120 milligrams of caffeine (a strong cup of coffee’s worth), and 30 milligrams of pyrilamine maleate, anantihistamine.

So what’s all that stuff supposed to do for you? Acetaminophen will probably help with the headaches and cramping but won’t do anything about those nasty inflammation-causing prostaglandins. Caffeine is a diuretic, which helps rid your body of excess fluid. But you can develop a tolerance to caffeine’s diuretic effects, so it will probably quit working after awhile.

Plus, caffeine can make PMS symptoms worse by ramping up anxiety, restlessness, and irritability—especially if you’re already getting caffeine from coffee or another source. And the antihistamine in PMS drugs is probably thrown in for its sedating effects, playing into the old notion that women with PMS just need to chill. Not cool!