As a proven muscle relaxant, peppermint may provide some relief from the pain associated with menstrual cramping. In a 2016 study, 127 women with chronic painful periods experienced reductions in the intensity and duration of menstrual pain. The outcome was just as effective with peppermint extract capsules as with a nonsteroidal anti-inflammatory drug. Nausea and diarrhea, however, were lower in the group taking peppermint than the group taking the pharmaceutical drug.