The effectiveness and safety of fluticasone propionate aqueous nasal spray (200 mu g once daily for 4 weeks) were compared with those of loratadine (10 mg once daily for 4 weeks) in 114 adults and adolescents with seasonal allergic rhinitis in this multicenter, double-blind, double-dummy, randomized, parallel-group study. Patients recorded their nasal symptoms (nighttime and daytime obstruction, sneezing, itching, rhinorrhea, and overall discomfort) using a 4-point scale (0 = no symptoms, 3 = very frequent symptoms) in daily diaries. Clinicians assessed patients' nasal symptoms (nighttime and daytime obstruction, sneezing, itching, and rhinorrhea) using a 4-point scale at every scheduled visit. Clinicians and patients assessed the overall effectiveness of treatment at the end of the study. Fluticasone propionate improved clinician-rated total nasal symptom scores (defined as the sum of five nasal symptoms) more than loratadine at the 2-week and 4-week assessments (P less than or equal to 0.008). Clinicians gave fluticasone propionate better global ratings than loratadine (P=0.04). After 4 weeks of treatment, between-group differences in clinician-rated individual nasal symptoms favored fluticasone propionate (P<0.05), with the exception of nasal itching (P=0.11). These findings were confirmed by between-group differences in the percentages of symptom-free days calculated from patient-recorded daily diary-card data. Both treatments were well tolerated. The incidence of adverse events between groups was similar. Fluticasone propionate aqueous nasal spray 200 mu g administered once daily in the morning was more effective than loratadine 10 mg administered once daily for the treatment of seasonal allergic rhinitis.