in 2002, the australian therapeutic goods administration (tga) found there were no legitimate medical uses for colloidal silver and no evidence to support its marketing claims. the u.s. national center for complementary and integrative health (nccih) warns that marketing claims about colloidal silver are scientifically unsupported, that the silver content of marketed supplements varies widely, and that colloidal silver products can have serious side effects such as argyria.