The invention relates to a biocide formulation for protecting, preventing or treating infections of the skin, comprising a combination of pentahydrate copper salts and heptahydrate zinc salts as active biocide compounds. Preferably, the copper salt is copper sulphate pentahydrate, and the zinc salt is zinc sulphate heptahydrate. In a preferred embodiment, the formulation comprises agents for improving the adherence to the skin. In another preferred embodiment of the invention, the formulation is suitable for use on the teats or udders of milking animals, between milking, for the treatment and prevention of mastitis.
