Methyldibromoglutaronitrile(MDGN) is a component of Euxyl K400, a preservative used in many skin care products in Europe. MDGN has been used in cosmetics in the United States and Korea. A sudden increased incidence of contact allergy from MDGN has been reported in 소디 United states. However, there has been no report in Korea. We report a case with persistent contact dermatitis from a cream containing Euxyl K400. Patch testing of cosmetics and of one of its ingredients, Euxyl K 400, revealed strong positive reactions. Upon testing 2-phenoxyethanol(one component of Euxyl K 400) and Euxyl K400 itself, Euxyl K400, not 2-phenoxyethanol showed a positive reaction. MDGN in Euxyl K400 is an important new sensitizer in cosmetics, with the increase of its use, it should be included in patch test battery of patients with allergic contact dermatitis. (Korean J Dermatol 2000;38(2)：283~285)