Objective: To compare the onset of action, efficacy, and safety of azelastine and levocabastine in the treatment of allergic rhinitis. Subjects and Methods: In a multicenter, randomized, double-blind, parallel-group trial, 244 patients with moderate-to-severe allergic rhinitis were randomized to receive either azelastine hydrochloride nasal spray (ANS) 0.1% or levocabastine hydrochloride nasal spray (LNS) 0.05% for 14 consecutive days. A visual analog scale was used to record total nasal symptom score (TNSS) changes. Indexes for further assessment included onset of action, total effective rate, and evaluation of therapeutic effect. Results: Statistically significant changes from baseline in TNSS were seen in both the LNS group and the ANS group. No significant differences were seen between the two groups in terms of evaluation of therapeutic effect, total effective rate, and onset of action, except for a higher symptom relief rate in the LNS group than in the ANS group within 30 min of administering the first dose. Adverse reactions were mild to moderate, with an incidence of 0.9% for LNS and 2.5% for ANS. Conclusion: Both ANS and LNS were effective and safe in the treatment of moderate-to-severe persistent allergic rhinitis. Moreover, LNS reached a higher symptom relief rate within 30 min of administering the first dose. Copyright (C) 2011 S. Karger AG, Basel