The NAD failed to get a substantive response from The Silver Edge, a company marketing its “colloidal silver” as a natural remedy to the influenza virus, and has now referred the matter to the FTC. Colloidal silver is a liquid slurry of silver particles, sometimes promoted as a dietary supplement, with no studies showing positive health benefits but plenty of evidence of serious side effects. The Silver Edge did not respond with support for the challenged claims that its product is effective against the flu and that the Center for Disease Control’s recommendation of the pharmaceutical product Tamiflu can “safely be ignored.”