The present invention provides a device for iontophoretic delivery of a drug to on into a tissue, comprising an arrangement that prevents operation of the device at a current density that is higher than a predetermined value, the arrangement including first means responsive to a first data item, indicative of the surface area through which the current is to pass, as to set the maximal current allowed at the surface area indicated by the data item. The present invention also provides a method for iontophorectivally administering drug to or into a tissue, comprising determination of a maximal allowed level of current density and preventing application of current density above the maximal allowed level.