Objectives : The aim of this study was to confirm whether or not coral has a preventive effect on development of atopic dermatitis induced by house mite(dermatophagoides pteronyssinus) in NC/Nga mice. Methods : This study was undertaken by using a reliable Atopic dermatitis mouse model demonstrating similar immune response. Lobophytum crassum was administered orally to NC/Nga mouse for 3 weeks. In order to verify the effectiveness of Lobophytum crassum in atopic dermatitis treatment, its role in immune factors were observed in NC/Nga mice. Results : ALT, AST, BUN and creatine levels were all within in the normal ranges in MC-1 200 and 400 (㎎/ ㎏) treated groups, indicating no induced toxicity. MC-1 200 and 400 (㎎/㎏) groups decreased of atopic dermatitis skin manifestation in NC/Nga mouse of MC-1 200 and 400 (㎎/㎏) groups compared to that of the control group and decreased the ratio of WBC and lymphocyte in blood. Also, MC-1 200 and 400 (㎎/㎏) groups significant decreased the ratio of CD4+, CD8+, CD11b+/Gr1+, B220/CD23 and CD4/CD25 immune cell ratio in ALN. Finally MC-1 200 and 400 (㎎/㎏) groups significantly increased the ratio of CD4+, CD8+, B220/CD23 and CD4/CD25 immune cells in DLN. Conclusions : Theses results suggested that Lobophytum crassum has suppressive effects on aberrant and overactive immunological activities in dermatophagoides pteronyssinus-induced dermatitis mice of NC/Nga.