Glucorticoid sprays are increasingly used for the treatment of allergic rhinitis and asthma. This therapy is highly effective, and side effects are few and mild. It was the aim of the present study to evaluate a physiological nasal inhalation technique, which results in airway deposition of the steroid molecule similar to that of inhaled allergen particles. Thirty adults with grass pollen-induced rhinitis and asthma inhaled the steroid molectile budesonide through the nose from a pressurized aerosol attached to a spacer device. Compared with inhalation of placebo, the treatment resulted in a significant reduction of nasal symptoms (P=0.005), of bronchial symptoms (P=0.005), bat not of eye symptoms. In addition, nasal peak inspiratory flow (P=0.0003) and oral peak expiratory flow (P=0.02) increased. There was no difference between budesonide and placebo with regard to local side effects, such as nose bleeding, hoarseness, and irritation in mouth and throat. It is concluded that nasal inhalation of a steroid from a spacer offers effective therapy of pollen rhinitis and asthma without significant local side effects. This therapeutic modality may have advantages over the ordinarily used nasal and bronchial spray treatment in patients with both rhinitis and asthma, especially when conventionel spray therapy is associated with local side effects.