Field of Science


The Shambulance: Ionic Foot Detox Baths

(The Shambulance is a brand-new, occasional series in which I try to convince you not to spend your money on bogus health products. My Shambulance copilot is Steven Swoap, a biology professor and physiology expert at Williams College.)

Regular water is so lazy. You put your feet in a warm tub and sure, it's relaxing. Maybe afterward you scrape some dead skin off your heels and put on lotion and feel a little more presentable in sandals. But don't you wish that water was doing some real work? Why isn't it, say, sucking poisons out of your whole body through the soles of your feet while curing your every ache, pain, and allergy?

If this is how you feel, you're in luck: Certain spas will happily take 50 or 75 of your dollars in exchange for half an hour of "foot detox." This warm water tub is no ordinary foot bath, but one that contains "positive and negative ions from a special generator" (an electrical current, in layman's terms).

What exactly does that current do? One Chicago spa claims that "your body will undergo a life-changing cleanse, releasing...toxins, oils, acids, fats, heavy metals, cellular debris, and waste that have accumulated over your lifetime." Removing all that bad stuff (which your body, for some reason, stubbornly clings to unless aided by electric foot baths) leads to a host of benefits. Possible health effects name-dropped by foot detox purveyors include pain relief, improvement of eczema and psoriasis, better organ functioning, increased energy, and greater muscle strength. And—because why not?—weight loss.

Just in case any skeptics are tempted to scoff, the foot bath people have proof their product is working. "It is an amazing process to watch," another Chicago spa declares, "as the presense of these cleansed toxins and waste are deposited back into the water around your feet in a murky display of residue."

Want the benefits of frequent detoxifying foot baths without having to pay for spa trips? You can buy your own machine (comes with carrying case!).

Before you pull out the MasterCard, though, you might reconsider a few points. For starters, the idea that harmful molecules can exit your body through the feet.

"We definitely have organs to rid ourselves of compounds that are not useful. You can call them toxins, but that word is so often used incorrectly that I try to avoid it," says physiologist Steven Swoap. "Those organs are the liver and kidney."

Our livers filter unwanted materials out of our blood and chemically modify them. Our kidneys send those materials into the toilet bowl. The soles of the feet are, if you can believe it, not part of the equation. "I imagine that in some alternate universe, organisms evolved an excretory organ on the bottom of their feet," Swoap says. "But not in our world."

In response to a long list of health claims from one spa's website, Swoap says, "If I report that I got sick from reading this, would that be a good scientific study?" He calls the wide-ranging promises "simply ridiculous." Increased energy? Cells get their energy from molecules such as adenosine triphosphate (ATP), not from some sort of internal housecleaning. More muscle strength? "It is not clear to me how running a small electric current in a bath can improve muscle strength," Swoap says. "Wouldn’t body builders just lie around in the stuff?"

The murky water doesn't prove much, either. "The residue is most certainly corrosion of the electrodes once you put in some salt water and a little current," Swoap says. "This is just like a corroded battery—all nasty and brown." Instead of removing metals from their bodies, users are soaking their feet in a bath of iron, nickel, or other metal from the machine's electrodes. ("Yum," Swoap says.) He points out that someone could easily demonstrate this by running the machine without any feet in it and producing the same residue.

You may remember foot gunk being used to sell another product: Kinoki foot pads, which popped up in the As-Seen-on-TV aisles a few years ago. Their makers claimed that wearing the adhesive pads on the bottoms of your feet overnight would draw out toxins from your body and, again, cure all your ills. The proof, they said, was in the gross brown material found on the pads in the morning. But a 2008 investigation aired on NPR revealed that used Kinoki pads were chemically identical to unused ones; the pads simply turned brown in the presence of moisture. In 2010, the Kinoki manufacturers were banned from marketing their foot pads after the FTC charged them with false advertising.

Any company that's selling cleansing and curing foot products may similarly be living on borrowed time. Instead of looking for miraculously hard-working water baths, why not take a moment to appreciate all the hard work your body is doing on its own? You might even thank it with a nice soak in a regular tub.


Thanks to Steven Swoap for helping me kick off the Shambulance road trip. Have a suggestion for a column? Write to me or leave a comment! 


  1. I was wondering about the truth behind this ever since getting a Groupon email for a Chicago foot detox last week--what perfect timing! I love the idea of this new series, too!

  2. I saw that Groupon too--it was actually what inspired the series! (As soon as I saw that more than 0 had been purchased, that is.)

  3. Nice read wad wondering after seeing one at a fair.

  4. Actually, I worked at an Herb Shoppe and Day Spa and took a detox foot bath just to see what results I could get. They tell you up front that the water will turn brown on it's own, that is no surprise. When I went, I had menstral cramps so bad I almost cancelled the appointment and went straight to bed, but decided to try anyway. By the end of the session, I was completely pain free and shocked by the fact as well. I am looking to schedule another appointment soon because I had such a remarkable experience.

    1. Liar!! You probly work at a spa trying to hustle innocent hard working people moneys!!! Machine cost like 100on ebay and charge customers 50 wtf

  5. > I had such a remarkable experience

    Ain't the placebo effect grand?


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