If an infant has diarrhea after stopping Montelukast, it may be caused by the infant’s primary disease not being cured or by the infant’s own digestive abnormality, so it is recommended to go to the hospital for examination. Montelukast is mainly used to treat acute and chronic diarrhea in adults and children. If an infant continues to have diarrhea after stopping the use of Montelukast, if the diarrhea is caused by bacterial, fungal or other infections, the medication may have been used for too short a period of time and the infant’s diarrhea has not been completely cured. If diarrhea persists after 1 day of taking Montelukast for acute diarrhea or after 2-3 days of taking Montelukast for chronic diarrhea, it is recommended to go to the hospital for examination and treatment. If the diarrhea is caused by improper feeding or climate change, it is mainly related to the infant’s own digestive function, and should focus on improving the infant’s diet and keeping warm, etc. It is not recommended to continue to take medication. When acute diarrhea occurs in infants, it is necessary to pay attention to hydrate the infant. A small number of people taking Montelukast may occur mild constipation adverse reaction, allergic to Montelukast is prohibited to use the drug.