Learn About Cough | American Lung Association

Learn About Cough

A cough is a spontaneous reflex. When things like mucus, germs or dust irritate your throat and airway, your body automatically responds by coughing. Similar to other reflexes like sneezing or blinking, coughing helps protect your body.

Key Facts

  • Coughing is an important reflex that helps protect your airway and lungs against irritants.
  • Occasional coughing is normal. It helps clear your throat and airway of germs, mucus and dust.
  • A cough that is persistent or associated with other symptoms like shortness of breath, mucus production or bloody phlegm could indicate a more serious medical problem.

What Is a Cough

Your throat and airways are equipped with nerves that sense irritants. Once stimulated, they send a signal to the brain. The brain, in response, sends a signal back to the muscles of your chest wall and abdomen to rapidly and forcefully take a deep breath in and out to remove the irritant. This response, is almost instantaneous and very effective. Coughing can propel air and particles out of your lungs and throat at speeds close to 50 miles per hour.

How a Cough Affects Your Body

An occasional cough is a normal healthy function of your body. Throats and lungs normally produce a small amount of mucus to keep the airway moist and to have a thin covering layer that works as a protective barrier against irritants and germs you may breathe in. Some infrequent coughing helps mobilize mucus and has no damaging effects on your body. Coughing also allows for the rapid removal of any unwelcome particles you accidentally breathe in.

As you grow older, muscles involved in coughing tend to lose power and your cough may not be as effective as it once was. This could lead to accumulation of mucus and ineffective removal of irritants from your throat and airways. This could put you at higher risk of lung infections, something commonly seen in older adults.

Although an occasional cough is normal, a persistent cough (one that doesn't go away) is not normal and should always be brought to your doctor's attention. Cough associated with other symptoms such as runny nose, acid reflux, shortness of breath, chest pain, increased mucus production, colored or bloody mucus is most likely an indicator of an ongoing disease and needs medical attention.

How Serious Is a Cough

How serious a cough is depends on what causes it. Some coughs last a short time and go away on their own, while others can persist until the cause is identified and treated.

Coughing is a common symptom of non-serious conditions, such as the common cold. It is also important to know that very serious diseases and conditions such as pneumonia, collapsed lung, lung blood clot and fluid in your lung can also cause cough.

People who have a history of smoking, chronic lung diseases such as COPD or asthma, seasonal allergies, acid reflux disease, lung cancer and chronic infections such as tuberculosis can have chronic cough.

Symptoms, Causes & Risk Factors »

    This content was developed in partnership with the CHEST Foundation, the philanthropic arm of the American College of Chest Physicians.


    Approved by Scientific and Medical Editorial Review Panel. Last reviewed July 13, 2016.

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