Background : The level of serum eosinophil cationic protein(ECP) is elevated in Atopic Dermatitis patients. Objective : The aim of this study was to investigate the usefulness of serum ECP as a tool of evaluate the efficacy of herb medicine for atopic dermatitis. Material and Method : We investigated 20 patients suffering from atopic dermatitis and analyzed the relationship among the serum level of ECP, IgE, Eosinophil count, and clinical disease activity. Result: Significant elevation in the serum level of ECP, IgE, Eosinophil count is observed in Atopic Dermatitis. Conclusion : The serum level of ECP may be considered to be an useful tool in evaluate effect of herb medicine for atopic dermatitis.