Fever and phlegm in the baby’s throat are mainly due to cold, rain, low immunity and other triggering factors, resulting in the invasion of the body by viruses, bacteria, mycoplasma, chlamydia and other pathogens, causing an inflammatory reaction in the mucous membrane of the respiratory tract and the throat. There will be corresponding congestion, edema, a large amount of inflammatory material exudation and lead to fluctuations in body temperature, or even a tendency to gradually climb, coughing and sputum discharge. At this time, blood tests can be performed, and if necessary, sputum from respiratory secretions can be taken for culture of pathogens, as well as for drug sensitivity tests to clarify the cause and to carry out symptomatic and anti-pathogenic treatment.