The effects of iontophoresis on biological aspects of the skin have received little experimental attention. despite the long history of this therapeutic mode. The clinical literature supports the contention that, in general, iontophoresis is a safe procedure. Nevertheless, unwanted cutaneous effects can occur, ranging from erythema through small punctate lesions to painful burns. Possible mechanisms hy which these arise involve the transfer of ions, a direct effect on nerves and high current density associated with skin appendages. Ways to counteract these cutaneous effects have been proposed.