Before menstruation, the release of prostaglandins in the body can cause disruptions in gastrointestinal function, which can lead to diarrhea. The symptoms do not last very long, but will end in 3-5 days, and will not affect your health, and are a sign of premenstruation. The symptoms of diarrhea can also be caused by the release of prostaglandins in the body when a woman has her period, which usually returns to normal after the period. The symptoms of diarrhea can also be caused by eating spicy and stimulating foods before menstruation, including some raw and cold foods, which stimulate the peristalsis of the intestines. As long as it is not particularly frequent, or diet to improve, you can eat more millet porridge or noodle soup, these foods can promote the recovery of intestinal function, to avoid the persistent occurrence of diarrhea.