Aworking definition of chronic obstructive pulmonary disease (COPD) is given within the GOLD Global strategy as a disease state characterized by airflow limitation that is not fully reversible. The airflow limitation is usually progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases. There is consensus that there has been a world-wide increase in COPD, reflecting increases in cigarette smoking, especially in developing countries. According to the Global Burden of Disease Study, in terms of lost disability-adjusted life years, COPD was ranked the 12th in 1990 and predicted to rise to the 5th ranking by 2020 and COPD was the sixth most common cause of death in the world in 1990 and will rise to the third most common by 2020. COPD is characterized by exaggeration of the normal inflammation response to irritant such as cigarette smoke. The mechanisms for this amplification of inflammation in COPD are not yet certain, but may be determined by genetic factors, latent viruses and impaired histone deacetylase activity. In addition to inflammation, extracellular matrix proteolysis. Cell death and ineffective repair are thought to be important in the pathogenesis of COPD.