If a child coughs up phlegm and can’t spit it out, first of all, he should drink more water, he should drink warm water in small amounts several times each time, so as to promote the dilution of phlegm, so that it can be easily discharged. You should give your child more pats on the back, especially when coughing, you should use the hollow palm, from bottom to top on both sides of the spine, to give your child a pat on the phlegm, each time the strength should be moderate, if too light may not achieve the effect. You can take some medicines to dissolve phlegm, if possible, you should do nebulization, nebulization of the drug is more direct action on the airway, will cause phlegm dilution as well as control the inflammatory response. If the cough is pronounced, you should go to the hospital, so that the doctor can determine the possible causes of the cough, so that symptomatic treatment can be carried out.