Tri-Nasal Nasal Spray is an investigational solution of triamcinolone acetonide (TAA) currently being evaluated as a treatment for allergic rhinitis. The safety and efficacy of 200 and 400 micrograms once daily doses of Tri-Nasal Nasal Spray, an active control (440 micrograms once daily of Nasacort Nasal aerosol), and Tri-Nasal Nasal Spray placebo were compared over a 2-week treatment period in a double-blind (the Nasacort treatment was not blinded), parallel design trial. A total of 377 adult patients in 13 centers were enrolled during the grass pollen season. The primary efficacy variable was the weekly average of the SSI (Symptom Severity Index), the sum of daily nasal congestion, rhinorrhea, and sneezing severity scores from the patient diary. A total of 355 patients completed the study. All active treatments were significantly more effective than placebo in relieving nasal symptoms at each treatment week. The 400 micrograms Tri-Nasal Nasal Spray and Nasacort treatments had a rapid onset of action, demonstrating significant improvement in the SSI versus placebo by the second day of treatment. Results for the individual nasal symptoms and other secondary efficacy measures paralleled those of the primary efficacy variables. Tri-Nasal Nasal Spray and Nasacort were comparable in safety, and in treating the nonocular symptoms of seasonal allergic rhinitis.