A wound dressing material comprising a solid bioabsorbable substrate dyed with an antioxidant dyestuff. The substrate may comprise collagen, chitosan or oxidized regenerated cellulose, and the dyestuff may for example be an aniline or acridine dye. The material preferably also comprises a silver salt, whereby the dyestuff stabilizes the silver salt. Also provided are methods of making such materials, and wound dressings comprising such materials.