The invention provides a method for preventing discoloration of pyrithione-containing materials, in particular plas-ticmaterials or other material such as paints, coatings, adhesives or textileswhich are exposed to an outdoor environment. Themethod is likewise suited for preventing discoloration of other pyrithione-containing materials such as personal care compositionslike shampoos. A discoloration inhibitor that includes dehydroacetic acid or asalt thereof is added to the pyrithione-containingmaterial. The discoloration is prevented without the addition of a cyclicorganic phosphoric acid ester or an organic phosphite.Use of the discoloration inhibitor does not interfere with the antimicrobialeffect of the pyrithione.
