 This study will be a randomized, double blind, placebo controlled, 3-way cross over design in allergic rhinitis subjects. Subjects will receive repeat doses of intra-nasal levocabastine for 7 days in each period and the duration of the study will be about 13 weeks. An Environmental Exposure Chamber EEC will be used in this study. The primary objective of the study is to investigate the non-inferiority effect of 7 days treatment with levocabastine on nasal symptoms elicited by an EEC when administered once daily QD compared with twice daily BID. Also study will be conducted to investigate the superiority of effect of 7 days treatment with levocabastine QD and BID on nasal symptoms elicited by an EEC in subjects compared to placebo. 