Disease analysis: Phlegm in the lung is mainly caused by lung infection, and anti-infective drugs can be used for treatment, such as levofloxacin, moxifloxacin, azithromycin and other drugs. If the yellow phlegm is not easy to be discharged, ambroxol hydrochloride tablets should be used for treatment. In addition, patients with chronic lung diseases, such as obstructive pulmonary disease and bronchiectasis. , need to check first, and then determine the treatment plan. Patients also need daily care to avoid inhaling cold air.