The authors have studied the effect of azelastine nasal spray in the treatment of seasonal allergic rhinitis. The trial was a double-blind, placebo controlled study, with 33 allergic subjects (17 female, 16 male), 15-40 years old. The patients were randomized into two parallel groups, to receive daily 0.56 mg of azelastine intranasally or placebo during two weeks. Before and after treatment severity of nasal symptoms such as: sneezing, itching, nasal blockage, nasal discharge and general feeling were evaluated by patients according to VAS (visual analogue scale). At the same time the physician's evaluation of nasal oedema, nasal discharge and general patient's condition were performed (VAS). Additionally during the treatment patients noted possible adverse events. Patient's and physician's evaluations showed clinical efficacy in the azelastine group and no evident efficacy in the placebo group--between those two groups statistical significances were noted for all evaluated parameters (p < 0.001). The bitter taste in the mouth was the only serious side effect in some patients in azelastine group, although this was quite well accepted. Generally the treatment was well-tolerated. Azelastine nasal spray is an effective and well-tolerated drug in the treatment of seasonal allergic rhinitis.