Abstract: A portable iontophoresis cold-contact electrode system having an outwardly raised, arched, electrically conducting electrode surface area (13) that can be cooled by a built-in sensor-regulated cooling element (30) in a defined way for the simultaneous cooling of the epidermis and the iontophoretic introduction of medicinal and cosmetic active substances through the epidermis into the underlying body tissue. In this process, the cooling of the epidermis makes possible an abrasion of horny skin cells on the skin surface, and also a conditioning and a better conductivity of the skin in order to funnel medicinal or cosmetic iontophoretic active substances more rapidly and more reliably through the human skin membrane into the underlying body tissue. The same electrode surface area can, if necessary, also be used to heat the skin by switching at the iontophoresis control unit if the individual conditions of the skin to be treated require it.