Sopungsan (SS) is a traditional Korean decoction used for the treatment of dermatitis. The aim of this study is to confirm whether or not SS has a preventive effect on the development of atopic dermatitis in dinitrochlorobenzene-applied Nc/Nga mice. SS was administered orally to Nc/Nga mice, which led to the remarkable suppression of the development of dermatitis, as determined by a histological examination and the serum IgE levels. Moreover, SS inhibited the production of thymus- and activation-regulated chemokine (TARC) and its mRNA expression in a keratinocyte cell line, HaCaT, which had been stimulated with tumor necrosis factor-${alpha}$ (TNF-${alpha}$) and interferon-${gamma}$ (IFN-${gamma}$). Activation of the nuclear factor-${kappa}B$ (NF-${kappa}B$) or activator protein-1 (AP-1) is one of key steps in the signaling pathways mediating induction of TARC. In this study, SS selectively suppressed NF-${kappa}B$ activation which may be essential for TARC expression in $TNF-{alpha}/IFN-{gamma}$ treated keratinocytes. The inhibitory effect of SS on NF-${kappa}B$ activation and TARC production might be associated with the anti-dermatitic effects of SS.