I'm sorry, I don't know a good comprehensive source on colloidal gold. Like I said, gold salts have been used in rheumatoid arthritis, and I think occasionally are still used for that purpose, but they can have some toxic side effects, so it's a question of whether the benefit exceeds the risk. Generally speaking, I would be wary of most remedies involving metals because they can often be toxic in human beings if ingested in any quantity. Certainly some medals have had medical uses for centuries. For instance, mercury used to be a standard treatment for syphilis. But it also caused some major side effects, so we are lucky today that people who contract syphilis can take antibiotics instead.