The aim of the study was to compare the efficacy and side-effects of oral antihistamine and nasal glucocorticoid therapy in seasonal allergic rhinitis. In a double-blind, double-dummy, group-comparative study, 60 birch and grass pollen allergic patients were treated with either loratadine (10 mg daily) or beclomethasone dipropionate (BDP) (100 micrograms in each nostril twice daily) during a 3 weeks' study period. Grading of 4 nasal and 3 non-nasal symptoms was performed at 4 weekly visits, and patients recorded daily symptoms and possible adverse experiences in a diary. Patients treated with BDP showed significantly less nasal blockage than those receiving loratadine (P less than 0.05), but there was no difference (P greater than 0.05) in other nasal symptoms (sneezing, itching and discharge). Patients treated with loratadine showed a statistically significantly greater relief in eye symptoms as compared with BDP (P less than 0.05). The side-effects caused by the 2 treatments were few and insignificant. We conclude that loratadine and intranasal BDP were effective in the treatment of seasonal allergic rhinitis, but the spectrum of individual symptoms controlled was different for the 2 drugs.