Methyldibromo glutaronitrile (MDBGN) is a bromine-containing preservative that has been used in cosmetic and toiletry preparations as well as in some industrial products. A maximum concentration of 0.1% MDBGN in stay-on and rinse-off cosmetics was approved for use in the mid 1980’s and animal tests showed it to be a weak sensitiser compared to other preservatives used at the time. By the 1990’s it became a commonly used preservative, particularly in cosmetic and self-hygiene products. However, methyldibromo glutaronitrile was soon discovered to cause allergic contact dermatitis reactions in eczema patients. Rates of sensitisation to MDBGN increased from 0.7% in 1991 to 3.5% in 2000 in patch test studies from 16 European centres. In the United States, sensitivity rates were up to 11.7%. In 2005, the European Union, banned the use of MDBGN in stay-on products, and then later in 2007 also in rinse-off products. Recent data from Europe observed a significant decrease in positive patch test reactions since the ban of MDBGN.