As a corticosteroid, Fluticasone works by blocking the release of certain natural substances that cause the symptoms of allergies and asthma. The oral inhalation form decreases irritation and swelling in the airways to improve breathing and relieve chest tightness, wheezing, and coughing. Fluticasone nasal spray reduces swelling and mucus in the nose to treat hay fever, rhinitis, and nasal polyps.