The present invention relates to materials having antimicrobial properties, said materials comprising a polymer having incorporated therein a synergistic combination of at least two metal oxide powders, comprising a mixed oxidation state oxide of a first metal and a single oxidation state oxide of a second metal, the powders being incorporated substantially uniformly within said polymer, wherein the powders have substantially different specific gravities and substantially similar bulk densities and wherein the ions of the metal powders are in ionic contact upon exposure of said material to moisture. There are further provided methods for the preparation of said materials and uses thereof, including in combating or inhibiting the activity of microbes or microorganisms.
