This multicenter, double-blind, randomized, controlled, parallel-group study compared the safety and efficacy of intranasal triamcinolone acetonide with oral loratadine in relieving symptoms of ragweed-induced seasonal allergic rhinitis. Patients from community-based allergy practices with a history of at least two seasons of seasonal allergic rhinitis verified by a positive skin test received either once-daily treatment with intranasal triacinolone acetonide 220 micrograms plus 1 placebo capsule or oral loratadine 10 mg plus placebo nasal spray. Other medications for rhinitis were prohibited. Changes in rhinitis symptoms were assessed by using patient evaluations, physician global evaluations, and withdrawal rates. Efficacy was evaluated in 274 of 298 patients randomized to treatment (134 to triamcinolone acetonide and 140 to loratadine). Mean total nasal symptom scores for weeks 1, 2, 3, and 4 and the overall score showed greater improvement (P = 0.001) with triamcinolone acetonide than with loratadine. Improvement in all rhinitis symptoms was significantly greater with triamcinolone acetonide than with loratadine; there was a trend for greater improvement in ocular symptoms with triamcinolone acetonide. Physicians' global evaluations indicated triamcinolone acetonide provided moderate-to-complete relief in 78% of patients compared with 58% of loratadine-treated patients (P < or = 0.0001). Both treatments were well tolerated; headache was the most commonly reported adverse event in both groups. Intranasal triamcinolone acetonide was significantly more effective than oral loratadine in relieving the symptoms of seasonal allergic rhinitis.