what is phlegm
Phlegm is more related to disease than is mucus. Phlegm is a secretion in the airway during disease and inflammation. Phlegm usually contains mucus with bacteria, debris, and sloughed-off inflammatory cells. Once phlegm has been expectorated by a cough it becomes sputum.hlegm is more related to disease than is mucus. Phlegm is a secretion in the airway during disease and inflammation. Phlegm usually contains mucus with bacteria, debris, and sloughed-off inflammatory cells. Once phlegm has been expectorated by a cough it becomes sputum.