Iontophoresis is a process of transdermal drug delivery by use of a voltage gradient on the skin. Molecules are transported across the stratum corneum by electrophoresis and electroosmosis and the electric field can also increase the permeability of the skin.These phenomena, directly and indirectly, constitute active transport of matter due to an applied electric current. The transport is measured in units of chemical flux, commonly µmol/cm2h. Iontophoresis has experimental, therapeutic and diagnostic applications.