Breathing with phlegm sound may be caused by acute and chronic bronchitis, lung disease and other reasons. 1. Acute bronchitis or chronic bronchitis can produce phlegm in the breath, usually accompanied by fever and cough. It is recommended to choose the appropriate treatment according to the viral or bacterial infection under the guidance of a doctor. 2. Chronic airway diseases such as bronchiectasis, chronic obstructive pulmonary disease (COPD), or lung infections may also cause these symptoms. If the bronchiectasis is combined with an infection, the patient may cough up a large amount of purulent sputum, usually related to body position. Pneumonia may be accompanied by cough, fever and even chest pain. When these symptoms occur, it is recommended to consult a specialist to determine the cause of the disease and to treat it as soon as possible.