People often experience some kind of blockage in the nasal passages or throat, persistent cough, and find it hard to breathe.
Phlegm is the thick viscous substance secreted by the mucous membrane of your respiratory tract whose role is to fight infections, especially in the case of a severe cold.
It accumulates in the throat and chest, thus congesting it and the body uses cough to expel it.
Excessive amounts of phlegm commonly occur in the case of cold, flu, sinusitis and viral or bacterial infections, as well as allergic reactions due to asthma, hay fever, or damaged vocal cords.