Eosinophilic airway inflammation is a pathological status characterized by obvious infiltration of eosinophils into the walls of trachea and bronchi.Asthma,cough variant asthma and non-asthmatic eosinophilic bronchitis are usual causes of chronic cough and all present with a common pathological process of eosinophilic airway inflammation.These evidences suggest that eosinophilic airway inflammation may have a close relationship with the pathogenesis of chronic cough and manifests different clinical phenotypes.