Feeling phlegm in the chest cavity when coughing indicates that the inflammatory site is often deep and is likely to reach the bronchi or lungs. First, go for a chest plain film or chest CT, and if there is indeed bronchitis or pneumonia, check the blood count, C-reactive protein and antibodies to mycoplasma, and preferably sputum culture. At this time, if there is a simple increase in C-reactive protein, the cough and sputum may be caused by a viral infection and will need to be treated with Xiyampin intravenous drip. If there is an elevation of leukocytes, neutrophils, and calcitoninogen, it is often caused by a bacterial infection and needs to be treated with intravenous ceftriaxone sodium or penicillin. If the patient is positive for mycoplasma antibodies, anti-inflammatory treatment with azithromycin or erythromycin may be indicated. In addition, it is best to use phlegm-reducing drugs, such as aminoglutethimide hydrochloride or compound fresh bamboo liquid, which are effective. In case of fever, antipyretic medication such as ibuprofen suspension is also needed.