Montelukast is one of the most commonly used antidiarrheal drugs in clinical practice, but it is not recommended that patients take it regularly, as it may lead to functional constipation and poor bowel movement. If a patient has frequent diarrhea, it is recommended that a clear diagnosis be made to find out what causes the diarrhea, whether it is ulcerative colitis or functional diarrhea, or diarrhea caused by other tumors. It is recommended that such patients take oral medications such as probiotics to regulate intestinal flora and gastrointestinal dynamics, rather than using montelukast for a long time to stop diarrhea, which can easily lead to intestinal flora disorders and other organic lesions.