Neonatal respiratory sensation of phlegm is often caused by the lack of development and maturity of the newborn’s own respiratory tract, which is easily stimulated by hot and cold external air, resulting in congestion and edema of the respiratory mucosa and exudation of small amounts of inflammatory material. Infections caused by pathogens, such as viruses, bacteria, mycoplasma, chlamydia and rickettsia, can also cause inflammatory reactions in the respiratory tract, resulting in the appearance of sputum and the feeling of phlegm. At this time, it is important to keep the newborn baby warm and avoid getting cold. Pat the baby’s back more often. If the symptoms worsen, you need to visit the neonatal unit and follow up at any time to prevent the emergence of lower respiratory tract infections.