Mesenchymal stem cells (MSCs) have arisen the attention to be a new attractive therapeutic tool treating autoimmune diseases such as allergic rhinitis (AR). AR is a chronic reversible allergic inflammation caused by the excessive activation of T-helper 2 (Th2) cells. Recently, MSCs have been proposed as a new therapy of AR as it can suppress some cytokines to control allogeneic Th2 response and functions. However, how MSCs function to reduce inflammation remains unclear. In this study, we aimed to investigate the role of ectomesenchymal stem cells (ECTO-MSCs) derived from nasal mucosa in eosinophilic inflammation and how it affects some immunoglobulins and cytokines. We used ovalbumin (OVA) as a sensitizer to induce nasal inflammation in mice by both injection and inhalation. In order to obtain deeper insights into the influences of ECTO-MSCs on nasal inflammation, the migration of ECTO-MSCs was assessed, the numbers of eosinophils and sneezing were counted, and several immunoglobulins and cytokines were measured. Here we show the ECTO-MSCs are able to migrate to inflammation site via tail vein injection. Eosinophils and sneezing were suppressed by ECTO-MSCs. Interestingly, IgE, interleukin (IL)-4, IL-5 and IL-10 secreted by Th-2 cells were down-regulated by ECTO-MSCs whereas IgG.sub.2 and IFN-[gamma] were up-regulated. In conclusion, we have observed that ECTO-MSCs are associated with enhanced Th-1 immune response to nasal inflammation and reduced Th-2 immune response. Given the contributions of Th-2 cells to AR, the injection of ECTO-MSCs can be a promising therapy of AR through balancing immune response.