http://nccam.nih.gov/health/silver/
  • The U.S. Food and Drug Administration (FDA) does not consider colloidal silver to be safe or effective for treating any disease or condition.
  • The FDA and the Federal Trade Commission (FTC) have taken action against a number of colloidal silver companies (including some companies that sell products over the Internet) for making drug-like claims about their products.
http://www.ncbi.nlm.nih.gov/pubmed/8632503
Silver products for medical indications: risk-benefit assessment.

.......... We emphasize the lack of established effectiveness and potential toxicity of these products.