Colonoscopy is not allowed during menstruation. When the patient is in the menstrual period, the endometrium is shed in large quantities, and the resistance of the uterus is relatively weak, so it is easy to be attacked by foreign pathogenic bacteria. When doing colonoscopy, the colonoscope will be sent into the rectum through the anus, the colonoscope in and out is easy to bring out the bacteria in the intestines, and the anus and genitals are closer, it is easy to cause bacterial infections, which can easily lead to endometritis, cervicitis and other diseases. If the patient needs anesthesia when doing colonoscopy, the anesthesia drugs may affect women’s menstruation, which may easily lead to the emergence of abdominal pain, bleeding and other symptoms. If patients do colonoscopy during menstruation, the blood flowing out is more likely to contaminate the instrument, causing bleeding in the intestines or anal bleeding and other diseases to be confused, so that the doctor is not easy to make a clear judgment on bleeding disorders. So don’t do colonoscopy during menstruation, you can do colonoscopy a few days after the end of menstruation.