Potential hazard of colloidal silver

Townsend Letter for Doctors and Patients, Feb, 2001 by Alan R. Gaby

A 56-year-old man presented with a several month history of bluish discoloration of the proximal areas of the fingernails, characteristic of argyria (silver poisoning). The serum concentration of silver was markedly elevated at 85 mcg/L (normal [less than]5 mcg/L). On further questioning, it was discovered that the patient had been taking 1 teaspoon of a colloidal silver product (containing 200 ppm silver) 3 times a day for the past 3 years, as an allergy and cold medication. Although the patient stopped using the colloidal silver product, there was no improvement in the appearance of his fingernails over the following 3 months.

Comment: Colloidal silver is promoted as a broadspectrum antimicrobial agent and an immune-system enhancer. It is claimed to be harmless at any concentration for both internal and external use. However, argyria is a well-known complication of prolonged exposure to silver-containing products. In addition to the nails, sun-exposed areas of the skin can also develop a blue-black discoloration. Although argyria is generally considered benign, the discoloration is usually permanent and is resistant to chelation therapy. The product labels accompanying colloidal silver preparations should warn the consumer about this potential side effect of long-term use.

Gulbranson SH, et al. Argyria following the use of dietary supplements containing colloidal silver protein. Cutis 2000;66:373-374.