Hyper-reactivity of the airway Bronchial reactivity refers to the contractive reaction of the airway to various stimuli including those chemical, physical or pharmacologic in nature. Airway hyper-reactivity(AHR) is defined as the excessive bronchial contraction in response to the stumuli which do not elicit response or only cause minor response under normal conditions ahR is one of the important characteristics of asthma, whilie airway imflammation is one of the most important mechanisms that contribute to ahrHyper-reactivity of the airway • Bronchial reactivity refers to the contractive reaction of the airway to various stimuli including those chemical, physical or pharmacologic in nature. Airway hyper-reactivity (AHR) is defined as the excessive bronchial contraction in response to the stumuli which do not elicit response or only cause minor response under normal conditions. AHR is one of the important characteristics of asthma, whilie airway imflammation is one of the most important mechanisms that contribute to AHR