”Phlegm” is a common problem for infants in daily pediatric clinics. Many parents are troubled or torn by their children’s “phlegm”, so what about “phlegm”? Normal people also have phlegm, but the “phlegm” is very little, just a small amount of mucus secreted to keep the respiratory tract moist; this situation does not require expectorant treatment. When inflammation occurs in the respiratory tract, the secretion increases and the amount of “phlegm” increases, and it can be white mucous phlegm or yellow pus phlegm. If it is a cold, bronchitis or pneumonia, you can choose cough medicine or antibiotics to treat it. If the baby with phlegm is in good spirits, has neither fever nor cough, eats and drinks and plays as usual, but has a snorting nose, parents’ attention should be drawn to it, such as uncomfortable foreign body feeling in the throat, irritating cough; some have nasal congestion, rubbing nose, picking nose; some snore at night and affect sleep; some babies always have swallowing action while having a snorting voice; some have been diagnosed with rhinitis; if the child has If the above situation occurs, the “phlegm” may not be real “phlegm”, but may be caused by rhinitis, and the “phlegm” comes from nasal mucus, which is caused by the backflow of nasal mucus to the throat. If the child does not spit up phlegm, then swallow it and excrete it with the digestive tract, but be sure to actively treat the rhinitis.