痛经主要是因为前列腺素的分泌，生理期刚开始还没来得及痛经时赶紧吃布洛芬可有效缓解当月疼痛，痛经开始后再吃没什么用。
Dysmenorrhea is mainly due to the secretion of prostaglandins; Taking ibuprofen can effectively relieve the pain of dysmenorrhea that month before menstruation begins, but taking it is useless to after dysmenorrhea begins.