The present invention relates to combinations of 4-bromo-2-(4-chloro-phenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile, or a salt thereof, and copper orzinc compounds which provide an improved protecting effect against foulingorganisms. More particularly, the present invention relates to compositionscomprising a combination of 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile, or a salt thereof, together with one or more copper orzinc compounds selected from Cu2O, Cu(OH)2, CuSO4, copper pyrithione, CuSCN,CuCO3, ZnO, ZnCl2, ZnSO4, zineb, and zinc pyrithione； in respectiveproportions to provide a synergistic effect against fouling organisms and theuse of these compositions for protecting materials against fouling organisms.This invention thus relates to the field of protection of materials, such asunderwater objects, protection of wood, wood products, biodegradable materialsand coatings.
