Phlegm in the windpipe and rumbling can be caused by asthma, lung infections, heart failure and other diseases, need to be treated for the cause. 1. Asthma: asthma is a common cause of phlegm in the airways and rales, especially in the acute attack of asthma, due to bronchospasm, and bronchial inflammation caused by bronchial mucosal congestion and edema, which can lead to the production of rales. Drugs such as albuterol need to be used promptly to relieve acute attacks. In the long term, the condition can be controlled by inhalation of drugs such as budesonide formoterol. 2. Lung infection: due to lung infection, sputum secretion can cause phlegm in the airways and bronchial spasm, resulting in croup, which requires timely anti-infective and sputum removing treatments. Generally, aminoglutethimide and bromhexine are used to resolve sputum, and acetylcysteine is nebulized to resolve sputum if necessary. If there is evidence of bacterial infection, antibiotics such as cephalosporins (cefixime) can be used to fight infection. 3. Heart failure: especially chronic left heart failure, due to the serious decline in the pumping function of the heart, resulting in pulmonary stasis, bronchial edema, causing narrowing or obstruction of the bronchial lumen, resulting in croup. Heart failure is usually relieved with digitalis drugs such as digoxin to strengthen the heart and diuretics such as furosemide and spironolactone for diuresis. Phlegm in the trachea and rumbling can also be caused by other diseases, if the symptoms are not relieved or aggravated, it is recommended to consult a doctor in time, improve the examination, clarify the cause of the disease, and follow the doctor’s instructions for treatment.