Background: SBP(桑白皮)is an herbal medicine which has been used in oriental medicine as a traditional therapeutic agent of bronchial asthma. Objective: This study was performed to investigate the effect of SBP on the anti-hypersensitivity and immune response in the murine of type I hypersensitivity induced by the experiment. Materials and Methods: Laboratory rats were primary sensitized with OA(ovalbumin); on day 1, rats of a Control group and Sample group (SBP group) were systemically immunized by subcutaneous injection of 1 mg OA and 300mg of Al(OH)3 in a total volume of 2ml saline. The rats of the sample group were orally administered with an SBP water extract for 14 days after primary immunization. On day 14 after the systemic immunization, rats received local immunization by inhaling 0.9% saline aerosol containing 2%(wt/vol) OA. A day after local immunization, BAL fluid and serum were collected from the rats. Total cell, lymphocyte, CD4+ T cell, CD8+ T cell, CD4+/CD8+ ratio in the BALF, and IgE level in serum were measured and evaluated. Results: SBP showed a suppressive effect on the immune response in the rats. 1. Total cells in the BALF decreased in the SBP treated group in comparision to the control group, but statistic differences were not observed. 2. Total lymphocytes in the BALF were statistically decreased in SBP treated group in comparision to the control group. 3. CD4+ T cells in the BALF were statistically decreased in SBP treated group in comparision to the control group. 4. CD8+ T cells in the BALF were not statistically different in SBP treated group and the control group. 5. The ratio of CD4+/CD8+ in the BALF was statistically decreased in SBP treated group in comparision to the control group. 6. The IgE level in serum decreased in the SBP treated group in comparision to the control group, but statistic differences were not observed.