An ion is a charged atom that has gained or lost an electron which creates a magnetic field capable of neutralizing oppositely charged particles. These neutralized particles are extracted from the body through a process called osmosis.
The body is composed of energy fields known as meridians, which connect your organs and run down to the sole of your feet. Since the foot also has 2,000 + sweat glands, this is the ideal surface to stimulate organs (via the energy meridians) and extract the toxins (from the sweat glands).