Abstract： Allergy,airway hyperreactivity (AHR),and allergic asthma are risk factors of chronic obstructive pulmonary disease (COPD),a heterogeneous disease presenting with various phenotypes.An allergic phenotype of COPD,characterized by more severe respiratory symptoms and higher risk of acute exacerbations,was described recently.[1] Further investigations into the role of allergy in the pathogenesis and/or expressions of COPD may lead to new modalities targeting the allergic component,a potentially treatable feature of a progressive disease like COPD.