Diarrhea during physiology is not necessarily normal. If the diarrhea is mild, it is usually caused by pelvic congestion, which is a normal physiological phenomenon; if the diarrhea is more serious, it is likely to be caused by abdominal cold, endometriosis and other reasons, which is not a normal pathological phenomenon. 1. Pelvic congestion: During the physiological period, the level of estrogen and progesterone decreases, the endometrium sheds blood, and the pelvis is in a state of congestion, which will stimulate intestinal peristalsis to accelerate, thus causing mild diarrhea symptoms. This is a normal physiological phenomenon that usually ends soon and does not cause a great impact on the female body. 2. Abdominal cold: If a woman in the physiological period because of wearing not warm enough or not covered at night, resulting in abdominal cold, cold air to stimulate intestinal peristalsis will also cause diarrhea symptoms. This is not a normal pathology. 3. Endometriosis: Women with a history of endometriosis may also suffer from diarrhea if the ectopic endometrial lesions invade the intestines during physiological periods, affecting the function of the intestines. This is an abnormal pathology. If you have diarrhea during physiological period, you should go to the hospital in time to find out the cause of the disease and follow the doctor’s instructions to standardize the treatment, so as not to delay the condition.