Colloidal silver: Is it safe?

My dad takes colloidal silver to maintain good health. It's true that he hasn't been sick in years, but I'd like to know if there are any good studies out there on the disease-fighting benefits of colloidal silver. Also, is it safe?

- Jane / Arizona

Mayo Clinic dietitian Katherine Zeratsky, R.D., L.D., and colleagues answer select questions from readers.

Answer

Colloidal silver is not considered either safe or effective in any of the health claims manufacturers make. No studies to evaluate colloidal silver have been published in reputable medical journals. Thus, all the claims for health benefits are based on manufacturers' opinions and anecdotes.

The Food and Drug Administration does not consider colloidal silver safe or effective to treat any disease or condition. Taking colloidal silver could have serious side effects, such as:

Argyria — an irreversible blue-gray discoloration of your skin, nails and gums
Seizures and other neurological problems
Kidney damage
Indigestion
Headaches
Fatigue
Skin irritation
Drug interactions with penicillamine, quinolones, tetracycline and thyroxine medications

Whenever you're considering taking a new dietary supplement, two questions are key:

Will this do what the manufacturer or advertiser claims?
Is it safe for me?

Your physician is your best partner to help you answer such questions. However, in the case of colloidal silver, with no reliable evidence of a benefit and lots of potential risk, it's best to leave the silver for your jewelry!