I'd never heard of this before, but argyria is caused by taking colloidal silver. Why would anyone do this? Rosemary Jacobs had it prescribed by her doctor in nasal drops back in the 1950s. She took it for four years, by which time she had turned silver. Argyria is rare, thank god, but a number of medications available over the internet apparently contain colloidal silver, which is why Ms Jacobs has rather bravely stood up and spoken up.