Whether phlegm in infants’ throat will heal on its own depends on the infant’s resistance, the cause of the disease and the severity of the condition. If the air is too dry in the room and there is no substantial respiratory infection, the condition can heal on its own after adjusting the air humidity. If the phlegm in the throat is caused by an upper respiratory tract infection, such as a common cold, and the child does not have symptoms such as nasal congestion or runny nose, and his or her resistance is relatively good, the symptoms can gradually disappear after 7-10 days of careful care. However, if the child has a cough with phlegm and a high fever, attention should be paid to reducing the fever and to avoid electrolyte disorders due to dehydration. In the case of lower respiratory tract infections, caused by bronchial mucosal secretions or lung inflammation, accompanied by coughing and spitting up, the baby’s resistance is poor, and most of these cases cannot be cured by themselves and need to be treated by a professional doctor. Since babies have weak resistance and immunity, parents should pay attention to feeding their babies reasonably, ensuring that the room temperature is appropriate and avoiding taking them to crowded places to avoid adverse effects on their health.