The effects of babies sleeping with their mouths open may increase the chances of respiratory infections, affect facial development and so on. 1. Increase the chance of respiratory infections: usually when the baby sleeps with his mouth open, because there is no nasal mucosa to remove harmful microorganisms in the air, resulting in many viruses and dust in the air may enter the lungs directly through the mouth. May increase the baby’s risk and chances of respiratory infectious diseases, such as easy pharyngitis, laryngitis, tonsillitis and pneumonia. 2. Impact on facial development: If the baby sleeps with his mouth open for a long time, it may also lead to abnormal maxillofacial development, and facial development may be affected in the long run. If parents find that the baby sleeps with his mouth open for a long time, it is recommended to go to the hospital in time to improve the nasopharyngoscopy and other examinations, to clarify the cause of the disease and then standardized treatment.