The causes of white sputum deep in the lungs that cannot be coughed up include the patient’s extreme weakness, lack of strength in the respiratory muscles, insufficiently strong cough reflexes, varying degrees of obstruction in the bronchial tubes, and thick sputum, and so on. 1. Extreme weakness of the patient: If the patient’s respiratory muscles are not strong due to extreme weakness, and the patient does not have the strength to cough or is worried about the pain when coughing, resulting in a low coughing strength, it will also lead to sputum in the lungs is difficult to cough out. 2. Cough reflex is not strong enough: due to problems in the respiratory center, the patient’s cough reflex is not strong enough or he/she will not cough voluntarily, which will also lead to sputum being difficult to be discharged. 3. Various degrees of obstruction in the bronchi: Whether the obstruction is caused by bronchospasm or obstruction caused by space-occupying foci, it may lead to sputum not being coughed up. 4. Thick sputum: When the patient has inflammation, especially when combined with bacterial infection, the sputum is often particularly sticky, which can also make it difficult to expel the sputum. The cause of white phlegm deep in the lungs, which cannot be coughed up, is very complex, and can be helped by turning over and patting the back, nebulized inhalation, and external expulsion of phlegm.