Dysmenorrhea

Ginger

In 2009 the Journal of Alternative and Complementary Medicine published a double-blind clinical trial in which 150 female students with primary dysmenorrhea took 250 mg ginger rhizome powder, 400 mg ibuprofen or 250 mg mefenamic acid 4 times per day for 3 days from the start of their menstrual period. Ginger was found to be as effective in relieving dysmenorrhea-related pain as ibuprofen or mefenamic acid. [Source]
In 2015 Archives of Gynecology and Obstetrics published a study which compared 250 mg ginger every 6 hours with to 250 mg of mefenamic acid every 8 hours (both from the onset of menstruation) on 122 students with moderate to severe primary dysmenorrhea. Ginger was found to be as effective as mefenamic acid without any adverse effects. [Source]

In 2008 the American Journal of Obstetrics and Gynecology published a controlled trial involving 649 patients which found that which women who received acupuncture saw greater improvements in dysmenorrhea-related pain and quality of life compared to a control group who received no acupuncture. [Source]