Colloidal silver

Colloidal silver is a colloid of silver particles in water. It has antimicrobial properties and was, in the past, used on external wounds and burns to prevent infection. Some claim that it is a beneficial nutritional supplement and a powerful antibiotic. As with many of the claims made for this product, there is no scientific proof of its efficacy as a treatment for illnesses such as anthrax following bio-terror alerts.[citation needed] The ingestion of colloidal silver in large quantities or over a long period of time carries a high risk of argyria, a condition in which the skin turns permanently blue-gray.