Will the colloidal silver products currently on the market turn you blue? The Harvard Health Letter says if you use them for a short time and in recommended amounts, probably not. But some people overdo it. For example, a 59-year-old man was sent to the emergency room because he looked cyanotic -- the bluish color that indicates a person is not getting enough oxygen. It turned out he'd been taking a homemade version of colloidal silver whenever he felt a cold coming on.