Coughing is a normal reflex action and is part of the body's defense mechanism to ensure the airways remain clean and protected from any foreign materials.
Coughing occurs when the body responds to irritants that have entered the breathing passages. These may include smoke, dust, and excess secretions such as mucus and phlegm. When an irritant is detected, the nerve system sends a distress signal to the cough centre of the brain which triggers the urge to cough.
Coughing can affect children and adults of all ages, it can be part of a wide range of unrelated disease, from a common cold to hayfever.
Coughing can be brief or it can last for several days, weeks or even months. Duration and severity of a cough will depend on the type and cause of the cough.