The present invention relates to combinations of a thiol group modulating enzyme inhibitor and a pyrion compound which provide an improved protecting effect against fouling organisms, fungi or bacteria. More particularly, the present invention relates to compositions comprising a combination of the thiol group modulating enzyme inhibitor zineb together with the pyrion compound zinc pyrithione in respective proportions to provide a synergistic effect against fouling organisms, fungi or bacteria and the use of these compositions for protecting materials against fouling organisms, fungi or bacteria.
