Recent epidemiological studies show that the prevalence of seasonal allergic rhinitis is increasing worldwide, and currently affects > 40% of paediatric individuals and 10%−30% of adults in the US alone. Symptoms include sneezing, watery nasal discharge and nasal obstruction, with severity ranging from mild to extremely debilitating. The impact of allergic rhinitis on health extends to predisposition of patients to comorbid asthma, sinusitis, conjunctivitis and otitis media with effusion. Poorly controlled allergic rhinitis may also cause sleep disturbances, and lead to learning problems among paediatric individuals. Thus, effective treatments are of great importance for controlling the symptoms of allergic rhinitis and positively influencing patients' QOL. Olopatadine is a second-generation antihistamine and mast cell stabiliser, which is marketed for the treatment of allergic rhinitis, allergic conjunctivitis, pruritus and urticaria. The efficacy of olopatadine for treating seasonal allergic rhinitis, and its effect on patients' QOL, were examined in several studies presented at a poster session at the 60th Annual Meeting of the American Academy of Allergy, Asthma and Immunology [San Francisco, US; March 2004].