Iontophoresis is an active transdermal drug delivery system that delivers drug ions through the skin using a low level electric current.

Direct Current is used to move a drug or therapeutically active ion through the skin. When direct current (DC) is applied to an ionized drug solution, the ions that have the same charge as the current are repelled by the current and are delivered through the skin. The aim is to drive active ions locally rather than having to inject them or have them taken systemically.