You tried: You've probably found that ibuprofen or Motrin IB (both referred to by docs as NSAIDs, or non-steroidal anti-inflammatory drugs) will help the pain—but you may not understand why this is. They block the pathways for chemicals called prostaglandins that cause contractions of the uterus, says Michele Curtis, professor of obstetrics and gynecology at University of Texas at Houston (by the way, Curtis says that those painful contractions some women feel during their period can be as intense as the ones other women feel during labor—so never again feel guilty about calling in crampy). NSAIDs not only relieve the pain, but also decrease the force of the contractions.
Likely mistake: Waiting to take a pill until you're practically doubled over. By this time, says Curtis, you have to play catch-up to get enough medication in your system to feel a difference. Next month, try taking NSAIDs 1-2 days before your period is due. If you suffer from serious cramps, Curtis suggests bumping up the dose to what she calls a therapeutic level of 800 mg every eight hours.
Keep in mind: Those at risk of GI or heart issues may want to lay off the ibuprofen (maybe you've already been taking it for a sport injury); some studies have shown that 200-500 mg of Vitamin E can help lower menstrual pain when taken two days before your period starts.
Next: Dr. Oz's 30-second pain fixes