Cough is a
protective reflex and it is your body's way of
getting rid of accumulation in the respiratory
tract. Coughs can be categorized by the duration
and productivity. Duration refers to how long
the person has to cough.
A productive cough, or wet cough
is one that produces some of the sputum (mucus
or phlegm) that protects the lungs. A
nonproductive cough, or dry cough is often the
result of irritation caused by mucus running
from the nasal passage to the throat.