The invention relates to an antimicrobial mixture containing 4-(3-ethoxy-4-hydroxy-phenyl)butan-2-one and an additional compound chosen from chlorhexidine digluconate, chlorhexidine hydrochloride and a polyhexamethylene biguanide salt, and also to a cosmetic composition containing such a mixture. Use in caring for, making up and cleansing keratin materials.