Norfloxacin can treat diarrhea caused by bacterial infections and can be used under the guidance of a doctor. Norfloxacin can impede the role of DNA rotase of pathogenic bacteria in the digestive tract, hinder bacterial DNA replication, and can play an inhibitory role on bacteria, which can effectively kill pathogenic bacteria such as Escherichia coli and Bacillus dysenteriae that cause intestinal infection, thus playing an antidiarrheal role. The following cases of diarrhea should not use norfloxacin treatment: 1, intestinal flora dysbiosis, irritable bowel syndrome people should not use norfloxacin treatment of diarrhea. Such patients use norfloxacin, the drug will not only kill the harmful bacteria in the intestine, but also kill the beneficial bacteria. Patients should not use the drug without authorization, and need to consult a professional doctor before using the drug; 2, indigestion or other non-infectious factors caused by diarrhea, should not use norfloxacin treatment, should use antidiarrheal drugs plus drugs to regulate digestion and absorption, such as montelukast, Bacillus licheniformis live capsules plus multi-enzyme tablets to achieve antidiarrheal effect; 3, norfloxacin has a delayed effect on the bone formation of minors, easily affect the development, so Minors with diarrhea are prohibited from taking it.