Inhibitory effects of allergic contact dermatitis of hot water extract of Duchung (Eucommia ulmoides Oliver) leaf, bark and stem growing at Sancheong-gun were investigated for female BALB/c mouse induced by repeat elicitation of DNCB (2,4-dinitro-chlorobenzene). Skin reactions, consisting of increased ear thickness and the presence of ear inflammation, were observed in mice treated with DNCB and Duchung. Weight of lymph node, spleen and thymus in mice treated with Duchung extracts were lower than that of mouse treated with DNCB. Ear weight of mouse treated with Duchung extracts was decreased by increasing the concentration of sample as compared to control group and dropped as low as control level at 1,000 mg/kg. Ear thickness became thinner as test time on Duchung extract progressed. MDA (malondialdehyde) contents in liver tissue were not different in sample group with DNCB group, but were different in ear tissue. NO (nitric oxide) contents was decreased in Duchung extract groups at serum and ear tissues as compared to 1% DNCB group. In the present study, the results suggested that Duchung extract inhibits inflammatory response and oxidative damage induced DNCB allergen.