I have had multiple people recommend to me that I should use colloidal silver to treat not only treat active infections, but as a preventative measure against future disease. One person even claimed that it could be used to cure AIDS, Ebola (this was during the Ebola outbreak), and many other things.
The thinking goes (as far as I understand it), nano-particles of silver can be used as a disinfectant, and many hospitals use this as a coating on certain surfaces to keep them clean without the use of caustic cleaning chemicals, so if you ingest the nano-particles of silver instead, they would kill the bacteria and viruses in your body, curing you of whatever infections you may have.
Personally, I haven't been able to find evidence for any of these claims, but I was hoping for a more definitive source on the matter. I was actually kind of surprised this hasn't been asked here yet since I hear so many people promoting this product.