This study was undertaken to compare the efficacy of twice-daily levocabastine, a new topical H1-blocking antihistamine, with that of twice-daily oral terfenadine in the treatment of allergic rhinoconjunctivitis. A total of 128 adult patients with a history of birch-pollen-provoked allergic rhinoconjunctivitis participated in this double-blind, parallel-group study. Ocular and nasal symptoms, assessed by a 100-mm visual analog scale, were recorded daily on diary cards for a period of 8 weeks. Global assessments of treatment efficacy were also performed. Conventional statistical analysis detected no significant differences between the two treatment regimens. Similarly, there was no difference in the number or type of adverse reactions in each treatment group. Statistical analysis according to Hauck & Anderson confirmed equivalence between the two treatment regimens. Topical levocabastine appears to be as effective and well-tolerated as oral terfenadine in the treatment of allergic rhinoconjunctivitis.