An agent for preventing and treating allergic rhinitis is provided to suppress eosinophilic inflammation and reduce T helper cell type 2 (Th2) immune response. An agent for preventing and treating allergic rhinitis comprises an stem cell which is derived from adipose. The stem cell is place on nasal mucosa. An agent for preventing and treating allergic asthma comprises the stem cell. The stem cell which is derived from an adipose suppresses eosinophilic inflammation and reduces Th2 immune response.