Ion Cleansing:

How the IonCleanse® Works
AC electricity is converted to low power DC electricity which flows through a patented electrode
system that sits in the footbath. The electricity and the metal combine to split the water
molecule into H+ and OH- ions. These ions travel through the body, neutralize oppositely
charged particles and through powerful osmotic pressure pull those neutralized particles out of
the body through whatever skin surface is in contact with the water.

For those with a scientific bent, the process described above is known as electrolysis of water,
and a detailed explanation of its biochemistry can be found at:

http://www.chem.uiuc.edu/clcwebsite/elec.html