Nasal application of grass pollen allergen in atopic individuals with seasonal rhinitis leads to an early rise in nasal airways resistance. The effects of fluticasone propionate, a powerful, topically active glucocorticosteroid, on nasal airways resistance and cellular infiltration of the nasal mucous membrane were investigated. Fluticasone propionate blunted the rise in nasal airway resistance following allergen challenge (P=0.089). Although this glucocorticosteroid did not affect the total number of eosinophils in biopsies of nasal mucous membrane, the number of activated eosinophils was significantly reduced (P<0.05). © 1990, Baillière Tindall. All rights reserved.