The present invention relates to a method of producing a hydrophilic polyurethane foam structure containing a silver salt, chosen from the group of silver sulphate, silver citrate, silver acetate, silver carbonate, silver lactate and silver phosphate, or a mixture of these salts. The method comprises the steps of (a) providing a water phase containing a surfactant, and at least one silver salt, wherein the at least one silver salt is dispersed in the water phase; (b) providing a isocyanate-terminated polyether having functionality of more than (2); (c) mixing said water phase and said isocyanate-terminated polyether, immediately transferring the resulting mixture to a mould whereby a foam structure is obtained; and (d) drying said foam structure until it has a moisture content of at most 10 % (wt). The invention also provides a hydrophilic polyurethane foam structure produced by the method and a wound dressing containing the foam structure.