Inside my bag from the natural foods market I found a flyer for colloidal silver. The ad called it a natural antibiotic and said it would be good for avoiding colds and flu this winter. I looked on the Web and some sites warn it will turn my skin bluish-gray. What’s that all about and is this stuff worth trying? - Gene

Sounds like the ultimate Halloween party trick: Something that keeps you alive, but makes you look dead. And though you’ll certainly scare a few kids and might startle anyone attempting CPR, the biggest drawback is the gray skin discoloration is permanent. A lifetime of blending into the asphalt is a high price to pay for the Best Costume Award.

Silver does indeed have antibiotic properties and has been used for these purposes for a few hundred years. Early settlers would often put a silver coin in their milk can to delay spoilage, and other cultures have stored water in silver vessels to keep it fresh. In more modern times, it’s used in medical preparations like skin creams, silver nitrate eye drops (now thankfully rare) for newborns, and burn dressings. Recently, Curad has come out with a new line of bandages containing a fine silver mesh that has been shown to retard bacterial growth. However, due to the price of silver, the company had to replace the usual cartoon characters printed on the bandages with little drawings of Warren Buffet.

Colloidal silver is simply a suspension of silver ions and/or silver particles in a pure water solution. Some preparations may also contain a protein like gelatin. The composition, particle size and purity vary greatly, so it’s difficult to know what you’re buying, even from the multi-level marketing companies that often promote it (why does that not surprise me?). Some companies caution it is so powerful, flushing even a little down the toilet will kill all the good bacteria in your septic tank. An interesting notion, but I wouldn’t buy stock in Rid-X just yet.

Claims are made that drinking, rubbing or inhaling the mist of this liquid can cure diseases from tuberculosis and shingles to HIV/AIDS. A few years ago the FDA took action against businesses making such claims and further categorized colloidal silver products as “not generally recognized as safe.” In response, many companies avoid the regulatory hassle associated with selling dietary supplements by marketing kits to make home-brewed colloidal silver. Not as profitable as moonshine, bootleg silver solutions might give you something more permanent than a hangover.

The blue-gray skin coloration is called Argyria, and occurs when silver accumulates in the tissues, skin, lips and nails. When acted upon by sunlight, the silver darkens to an irreversible black pigment in a process similar to developing a photograph (except it’s always Ansel Adams, never Annie Leibovitz). Though this is fairly rare, it is more common with long-term daily use or high strength silver solutions.

Having given all the warnings, there does seem to be some evidence of benefit in stubborn drug resistant, skin related conditions. However, there is absolutely no proof of effectiveness in any internal disorder or illness. So, under the care of an experienced physician or naturopath, I would advise only external application of laboratory certified colloidal silver products. Further, you should limit its use to specific short-term conditions and definitely abstain from daily supplementation.

Silver is not essential to your diet (except as part of the place setting); you won’t suffer any deficiencies without it. And although you might have to endure the flu this coming winter, it seems a fair trade to limiting your job prospects to playing the Tin Man at the local dinner theater.

Dr. Ed Rabin is a chiropractor practicing in Boise, Idaho. Send your nits to pick and health related questions to theantidote@edrabin.com (www.edrabin.com).