The phlegm in the baby’s nasal cavity is not actually phlegm produced by the airway, it should be big nasal snot. Because babies can’t blow their nose and don’t have the ability to pick it outward by themselves, especially children, they feel a whirring sound in the oropharynx and nasal cavity when they breathe, which is actually nasal congestion. The nasal mucus does not flow out completely, blocked in the nasal cavity, with breathing will appear this symptom. This condition is most often seen when the baby is cold, or when the weather is dry or overheated, as well as rhinitis caused by upper respiratory tract infections. This is because the baby is now small, the mucous membrane of the nasal cavity is rich in attached blood vessels, so when infection or stimulation occurs, it is easy to cause congestion and swelling of the mucous membrane, resulting in nasal congestion, increased secretions, and the sound of whirring and grunting. It is recommended to spray the nasal cavity with physiological sea saline spray, which has the effect of flushing the nasal cavity and flushing out the secretions.