Background: Although response to intranasal corticosteroid therapy has been reported in patients with nonallergic rhinitis with eosinophilic syndrome (NARES), efficacy specifically in non-NARES patients has not been fully characterized. Objective: To evaluate the efficacy of intranasal fluticasone propionate (FP) in the treatment of patients with perennial nonallergic rhinitis, with and without nasal eosinophilia. Methods: Data from 983 patients in three randomized, double-blind, placebo-controlled PNAR trials were integrated. Patients received a total daily dose of FP 200 mug (n = 332), FP 400 mug (n = 325), or placebo (n = 326) for 28 days. Patients were 12 years of age with perennial rhinitis and negative skin tests to all allergens relevant to the geographic region. Nasal eosinophils were evaluated using a five-point scale. Patients were classified as non-NARES with a point score of 0 (n = 674; 69%); patients with a point score between I and 4 were classified as NARES (n = 309; 31%). Efficacy of FP was evaluated by the mean change in total nasal symptom score (TNSS), a sum of patient ratings of nasal obstruction, postnasal drip, and rhinorrhea. Results: Patients with either NARES or non-NARES had similar statistically significant improvement with FP 200 mug or 400 mug compared with placebo, thus, the total group comprising both varieties of rhinitis responded to FP. In the total population, both FP treatment groups showed significantly greater improvement in TNSS compared with placebo during each week of treatment (P less than or equal to 0.002), with mean changes in TNSS for day 22 to day 28 ranging from -84 and -85 in the FP 200 mug and FP 400 mug groups, respectively, to -64 in the placebo group, The three study treatment groups had similar proportions of non-NARES (68 to 69%) and NARES (31 to 32%) patients at baseline. In the non-NARES subgroup, mean changes in TNSS for each treatment group were similar to changes seen in the total population. In the NARES subgroup, mean changes in TNSS for the FP 200 mug and placebo groups were similar to changes seen in die total population; mean change in TNSS for the FP 400 mug group was somewhat greater than changes seen in the total population. Conclusions: Intranasal FP is an effective treatment for perennial nonallergic rhinitis with or without nasal eosinophilia (NARES or non-NARES).