In a double-blind study involving 205 patients with perennial allergic rhinitis, statistically significantly greater symptomatic improvements were evident following the administration of 200 micrograms/day triamcinolone acetonide aerosol than following placebo. These improvements were evident as early as week 1 and were sustained throughout the 12-week study. They were accompanied by greater reductions in nasal eosinophils. Triamcinolone acetonide aerosol was well tolerated and had no effect on serum cortisol levels.