The reasons why patients have sputum and cannot cough up are to be analyzed specifically, as follows: 1. Sputum is sticky: because patients’ sputum is more sticky and difficult to cough up, it is usually seen in purulent sputum caused by bacterial and/or fungal infection of the lower respiratory tract. 2. Coughing up sputum is weak: sputum cannot be effectively coughed up and stays in the bronchi, especially in patients who are bedridden for a long time, the elderly, and patients who are more exhausted. 3. Some bronchial lesion: for example, local bronchial stenosis or obstructive pneumonia formation, which makes it difficult to cough up phlegm effectively. 4. chronic pharyngitis: patients feel that there is a foreign body in the throat and cannot cough up phlegm because they feel that there is phlegm stagnant in the throat. Therefore, for patients who cannot cough up phlegm, they must be treated symptomatically for their causes.