The symptoms of sputum obstructing the airway depend on its specific condition. Phlegm obstruction of airway refers to excessive phlegm or sticky phlegm that cannot be discharged effectively in time, resulting in corresponding clinical symptoms of patients, which are as follows: 1. Obstruction of lower bronchus: If phlegm obstructs lower bronchus, patients may have wheezing symptoms that are not obvious, and at this time, patients can have different degrees of coughing, and some patients have fever and other phenomena due to secondary lung infection. 2. Obstruction of upper bronchus: When phlegm obstructs the trachea, especially the upper segment of the trachea, patients can mostly have different degrees of wheezing and shortness of breath. If the upper trachea or throat is blocked by phlegm, the patient can also have sudden respiratory difficulty and irritability. Severe patients may even have respiratory failure and facial cyanosis, and a few patients may die of asphyxia. Therefore, when there are symptoms of sputum obstructing the airway, timely symptomatic treatment should be given according to the condition in order to improve the clinical symptoms.