Abstract: There is provided an antimicrobial composition comprising a diiodomethyl sulfone of the formula R(CH.sub.2).sub.n SO.sub.2 CHI.sub.2, wherein n is an integer from 0 to 4 and R is selected from the group alkyl, cycloalkyl, phenyl, naphthyl, loweralkylphenyl, polyloweralkylphenyl, lower-alkoxyphenyl, monohalophenyl, polyhalophenyl, haloloweralkylphenyl halonitrophenyl, nitrophenyl, nitroloweralkylphenyl, anilino, anilinophenyl, and anilamidophenyl and in order to prevent the yellowing and/or the discoloring of the diiodomethyl sulfone a compound containing a reactive sulfide or sulfhydryl group. If the compound containing a reactive sulfide or sulhydryl group is a dithiocarbamate the composition shows an increased antimicrobial activity.