Eating metronidazole cause bowel movement may be the reason why metronidazole plays a role in balancing the intestinal flora, disinfecting and sterilizing, and its own efficacy to play the role of high efficiency. 1. The intestinal tract is mainly Escherichia coli, anaerobic bacteria, metronidazole can inhibit anaerobic infections, play a balanced intestinal flora, control the growth of intestinal flora, can promote normal defecation, stool shaping and so on. 2. If there is coloproctitis, bacillary dysentery, metronidazole has the role of disinfection and sterilization, can improve coloproctitis, bacillary dysentery symptoms, promote the recovery of the condition, promote normal bowel movements. 3. Artificial oxalic metronidazole itself has the effect of detoxification, detoxification, the human body detoxification can be through defecation, therefore, may indirectly play a role in promoting the efficacy of bowel movement. Drugs need to be used under the guidance of a doctor.