Chronic obstructive pulmonary disease , also known as COPD is a chronic lung disease of airflow limitation that is associated with abnormal inflammatory responses and increased mucus production. In COPD there is blockage of the airflow in the passages of the lungs, which results in decreased airflow and exchange. Common symptoms of COPD include a chronic cough and shortness of breath.
Two types of COPD exist; emphysema and chronic bronchitis. Emphysema results in the enlargement of air spaces and air trapping in the lungs while chronic bronchitis leads to a persistent cough and excess mucous production.

According to the Center for Disease Control and Prevention, the prevalence of COPD in the US is about 34 million individuals.  COPD is the third largest cause of death in in United States and typically occurs in middle age to later years of life.

The primary cause of COPD is the use of inhaled tobacco smoke. About half of all smokers show minor changes of COPD in the lungs, while a quarter of smokers who have a long history of chronic smoking will develop the disease. Second hand smoke can also cause COPD. The sooner the patients quits smoking, the less of a chance of they will have of developing COPD.