The present invention is related to a biocide formulation to protect, prevent or treat skin infections in a combination of pentahydrate copper salts and heptahydrate zinc salts as active biocide compounds. Preferably, the copper salt is pentahydrate copper salt and the zinc salt is heptahydrate zinc salt. In a preferred realization, the formulation comprises agents to enhance adhesion to the skin. In another preferred realization of the invention, the formulation is suitable to be applied to the teats or udders of the milking animals, inter milking, for the treatment and prevention of mastitis.
