AimsIn this study, we evaluated the therapeutic efficacy of selected probiotics in a mouse model of birch pollen (BP)-induced allergic rhinitis. Methods and ResultsOral administration of Lactobacillus plantarum CJLP133 and CJLP243 ameliorated the symptoms of BP-induced allergic rhinitis by reducing airway hyperresponsiveness, and both the histological scores and the number of infiltrated cells in the nasal cavities and lungs. Compared with those from vehicle-treated mice, bronchoalveolar lavage fluid and draining lymph node samples from CJLP133 and CJLP243-administrated mice showed diminished numbers of immune cells, increased secretion of a Th1-type cytokine (IFN-) and decreased production of Th2-type cytokines (IL-4, IL-5 and IL-13). Consistent with these results, levels of IL-4, IL-5, IL-13, serum IgE and BP-specific serum IgG1 were decreased, whereas secretion of IFN- and BP-specific serum IgG2a was augmented upon administration of CJLP133 and CJLP243 in mice. ConclusionOral administration of L. plantarum CJLP133 and CJLP243 alleviates symptoms of BP-induced allergic rhinitis in mice by recovering Th1/Th2 balance via enhancement of the Th1-type immune response. Significance and Impact of the StudyLactobacillus plantarum CJLP133 and CJLP243 have therapeutic effects on BP-induced allergic rhinitis in an animal model.