Fluticasone propionate (FP) is a topical corticosteroid with minimal systemic activity. We examined safety and compared the efficacy of FP aqueous nasal spray, 200 μg every day with loratadine tablets, 10 mg by mouth every day in 240 adolescents with ragweed pollen–induced seasonal allergic rhinitis for 4 weeks in a randomized, double-blind, parallel-group study. Nasal and eye symptoms were recorded daily on a 4-point (0 to 3) scale. A higher percentage of symptom-free days was observed for nasal blockage on waking during treatment with FP (p < 0.0001). Significant results were also obtained for all other nasal symptoms when analyzed for both symptom-free days and symptom scores. No differences were found for eye irritation symptoms (p = 0.14). Morning and evening nasal peak inspiratory flow (PIF) was recorded daily by 57 subjects. FP treatment was associated with significantly higher PIF values than loratadine both morning (p = 0.0051) and evening (p = 0.0036). A greater improvement over 4 weeks was observed for PIF morning values in the FP group (p = 0.008) but not for evening values (p = 0.358). Statistically significant correlations were found for nasal blockage and PIF in the morning (r = -0.54, p = 0.0001) and in the evening (r= -0.46, p = 0.008). (J ALLERGY CLIN IMMUNOL 1996;97:588-95.)