Chest phlegm can not be coughed up after a cold, you can take the following aspects of treatment: First, symptomatic treatment, the use of expectorant drugs, such as aminobromine, eucalyptus pin, acetylcysteine, etc.; Second, the causal treatment, improve the blood routine, C-reactive protein, chest radiographs, mycoplasma antibodies and other related tests to assess the possible infection of causative organisms, according to the causative organisms to take the appropriate treatment. If the patient has elevated white blood cells, consider bacterial infection, use penicillin v potassium tablets, amoxicillin, cefixime, azithromycin and other related drugs for treatment. If the patient has more than four-fold elevation of mycoplasma recent antibody, it is considered to be an atypical pathogenic bacterial infection, and can be treated with macrolides, such as azithromycin, erythromycin, or quinolones, such as levofloxacin, moxifloxacin, and other related drugs.