The relationship between allergic thiniris and bronchial asthma is controversial. To assess the relationship, we sought to determine the effect of nasal allergen exposure on lower airway reactivity in subjects with allergic rhinitis and asthma. Airway Hyperresponsiveness was evaluated by methacholine bronchial provocation test in basal conditions and 16 hours after specific nasal provocation test with D. pteronyssinus (6 subjects), D. farinae (1 subject), or ragweed (1 subject) allergens. Nasal provocation test was performed by applying paper disks soaked with increasing concentrations of allergen extract solutions to the inferior turbinates of both sides of the nose until a positive response was achieved. Responses to nasal provcoation test were evaluated by means of provoked symptoms and nasal flow resistance determined by anterior rhinomanometry. There was no significant difference between basal and post-challenge FEV1. All subjects developed severe rhinitis symptoms during the nasal challenge. The degree of nonspecific bronchial hyperresponsiveness determined by PC20 methacholine was not significantly changed. This study suggests that bronchial hyper responsiveness does not change after nasal allergen challenge in subjects with allergic rhintis and bronchial asthma.