Background and Objectives : Atopic dermatitis is a recurrent or chronic eczematous skin disease with severe pruritus,and has increased in Korea. Although the pathogenic mechanisms of atopic dermatitis are yet unknown, recently skin barrier dysfunction and hyperresponsive Th2 cells in the acute phase have been reported as important mechanisms. Cheonggi-san(CGS) is used in oriental clinics for treatingacute skin lesions of eczema or urticaria. There have been no studies on the therapeutic mechanism of CGS for curing atopic dermatitis. We aimed to find out the therapeutic effects of its internaluse on atopic dermatitis-like skin lesions, induced in NC/Nga mice by the mite antigen D. pteronyssinus and disrupting skin barrier. Materials and Methods : The NC/Nga mice were classified into three groups: control group, atopic dermatitis elicitated group(AD), and CGS treated group (CT). Atopic dermatitis-like skin lesions were induced on the back of female NC/Nga mice, 12 weeks of age, by tape stripping, 5% SDS applied to disrupt skin barrier and painting 3 times a week with D. pteronyssinus crude extract solution for 3 weeks. CT was treated with CGS orally after atopic dermatitis was elicitated. We observed changes of skin damage, mast cells, substance P, angiogenesis, skin barrier, Th2 cell differentiation, nuclear factor-${kappa}B(NF-{kappa}B)$ p65 activation and COX-2 in NC/Nga mice with atopic dermatitis-like skin lesions. Results : The skin damages as eczema were seenin AD, but mitigated in CT. The degranulated mast cells in dermal papillae increased in AD, but decreased in CT. The substance P positive reacted cells in CT remarkably decreased. The angiogenesis increased in AD, but decreased in CT. The decrease of lipid deposition and ceramide in AD was seen, but anincrease of lipid deposition and ceramide in CT was seen. The distribution of IL-4 positive reacted cells in dermal papillae increased in AD, but decreased in CT. The distribution of NF-${kappa}B$ p65 positive reacted cells & COX-2 positive reacted cells in CT decreased. Conclusion : The results may suggest that the CGS per os decreases the dysfunction of the skin barrier, inhibits Th2 cell differentiation and inhibits NF-${kappa}B$ p65 activation in NC/Nga mice with atopic dermatitis-like skin lesions.