What are the side effects of colloidal silver?

The primary side effect of colloidal silver is argyria, which is an irreversible formation of gray and blue spots on the skin, states Healthline. Other side effects include kidney damage, seizures, liver disease and vision problems.

Although manufacturers of colloidal silver claim that this product boosts the immune system, treats cancer, and fights bacteria and viruses, the Food and Drug Administration does not recommend its use for any health condition, stresses Healthline. As of 2015, the purpose of colloidal silver in the body is not known, but it can build up in the body, interfering with medications such as penicillamine, thyroxine, tetracycline and quinolone antibiotics, advises Mayo Clinic.