This study was performed to compare the effect of Platycodi Radix (PG) and Black Platycodi Radix (BPG; developed from fresh Platycodon grandiflorum root by steaming nine times at 80°C for 36 hr and drying nine times at 30°C for 24 hr , at which point it becomes black in color.) on anti-oxidant effect, anti-bacterial properties and ovalbumin (OVA)-induced allergic asthma mouse model by calculating serum cytokines and IgE. To induce the allergic asthma, in the control group and the sample treated group, mice of each group were sensitized intraperitoneally with OVA solution at the 1st, the 7th and the 14th day. Sensitization was performed by aerosol allergen challenges with 1% OVA solution intratracheally at the 21th, the 23th, the 25th and the 27th day. At the 29th day, the mice were killed and the levels of interferon-γ, interleukin-4, 5 and 10, total IgE and OVA-specific IgE were measured. IFN-γ was not different among the PG, BPG, and control groups. IL-4, IL-5, IL-13, total IgE, and OVA-specific IgE were significantly in the BPG group compared with the control group. Considering the above experimental results, this study showed that nine times-repitative steaming process on the roots of Platycodon grandiflorum could enhance reduction of the allergic reaction by reducing level of OVA specific IgE and immune cell infiltration and restoring Th1/Th2 cytokine imbalance.