Iontophoresis is a noninvasive process that transports drugs through the skin without needles. In the photo, the red electrode is positive and the black electrode is negative. The electric field between the electrodes will drive the negatively charged molecules of an anesthetic through the skin. Should the drug be placed at the red or the black electrode

Follows are the explanation to this question:

Explanation:

When the drug is negatively charged, its negative electrolyte is annihilated to just the positive electrode. It is enticed, and it may not have a picture showing the electrode, however, We suppose that electrodes from either side of a skin slice. Its negative electrode will bypass or push thru the skin if in front of the counter terminal this becomes a red-positive electrode.