Thirty-five patients with seasonal pollen rhinitis due to hypersensitivity to Parietaria officinalis pollen were randomized and treated with ketotifen and with a combination of ketotifen and beclomethason diproprionate, a nasal steroid. The study was timed to cover the Parietaria off. pollination period (4 months), which was documented by the determination of air concentration of the pollen. Respiratory symptoms and additional medications were scored according to a defined control. During the peak pollen period, both groups suffered from intensified pollinosis symptoms which prompted additional medication. The increases, however, were less significant in the group treated with the combination of the two drugs, i.e. better results were obtained with the ketotifen-beclomethasone diproprionate combination than with ketotifen alone.