Our results indicated that 7,8,4′-THIF, a metabolite of the soy isoflavone daidzin, suppresses the development of DNCB-induced dermatitis in NC/Nga mice, probably by down-regulating various Th2- (TARC, IL-4, IL-5, and IL-13) and Th1-associated factors (IL-12 and IFN-γ). This evidence concerns the gene IL4 and dermatitis.