a germicidal absorptive material for use in surgical packings , sanitary tampons and similar uses is provided by a sponge - like matrix of polyvinyl alcohol - acetal copolymer to which is tightly bound a germicidal disinfectant dye . polyvinyl alcohol - acetal polymer shows exceptional avidity for a number of disinfectant dyes , both acidic and basic , such as methylene blue and gentian violet . consequently , sponges of this material containing disinfectant dye release no dye to an aqueous solution the material is generally a porous matrix that releases no particles or fines into wounds or body orifices . presence of bound disinfectant dye allows the sponge to inhibit bacterial growth in a number of different situations . several common bacteria are killed by being incubated in the present of an embodiment of the invention which contains both methylene blue and gentian violet .