A cough is a reflex action to clear your airways of mucus and irritants such as dust or smoke.
Coughs may be dry or chesty (see box below). They're also classified according to how long they last:
- acute cough lasts for less than three weeks
- subacute cough gets better over a three-to-eight-week period
- chronic (persistent) cough lasts for longer than eight weeks
Coughs caused by the common cold or by flu usually clear up after several days. Most coughs clear up within two weeks.
For more information on treating cough, go to Treatment.
What are the causes?
Most people with a cough have a respiratory tract infection caused by a virus, such as the common cold, flu or bronchitis.
A persistent cough in adults may be caused by a condition such as rhinitis, or by a prescribed medicine such as an angiotensin-converting enzyme (ACE)-inhibitor, which is used to treat high blood pressure or cardiovascular disease, or by smoking.
In children, a persistent cough may indicate a more serious respiratory tract infection such as whooping cough.
For more information on conditions that cause cough, go to Causes of cough.
When to see your doctor
See your GP if you've had a cough for more than two weeks after a viral infection, or if your cough is progressively getting worse.
