It has been 40 years since Niels Mygind's publication in British Medical Journal on intranasal application of beclomethasone dipropionate aerosol in allergic rhinitis (AR). Since then a new era in treatment of allergic and nonallergic upper airway diseases began. This publication presents current concepts on application of intranasal glucocorticosteroids (inGCS) in treatment of upper airway diseases and in particular of AR and rhinosinusitis. Nonquestionable advantage of inGCS is their strong anti-inflammatory local action with little impact on general health responsible for few and benign side effects. Main way of action of glucocorticosteroids is connected with binding to the intracellular glucocorticosteroid receptor and its impact on nuclear cytoplasmic transcriptional factors. Glucocorticosteroids suppress gene expression of factors responsible for generating and supporting inflammatory processes, proinflammatory cytokines and chemokines production, and adhesive molecules expression. It appears that glucocorticosteroids have also other mechanisms of action, non-involving intracellular receptors, leading to inhibition of early and late phase of allergic reaction. At the moment the following glucocorticosteroids are registered in Poland: beclomethasone, budesonide, fluticasone propionate, fluticasone furoate, and mometasone furoate. Furoates earn special attention as their lateral furoate ester chain makes the molecules highly lipophilic, and hence easily absorbed by nasal mucous membranes, epithelium and cell membrane phospholipids. This minimizes their general action and maximizes local action. According to current state of knowledge topical glucocorticosteroids are used in the following upper airway diseases with different inflammatory mechanisms: AR, non-AR, particularly NARES, acute rhinosinusitis, chronic rhinosinusitis with and without nasal polyps, adenoid hypertrophy and rhinitis in bronchial asthma.