Colloidal silver is a suspension of microscopic silver particles in a liquid, usually water. It has been used as an antibacterial agent since the late 19th and early 20th centuries. In recent years, however, it has been largely replaced by modern antibiotics.
Some people claim that colloidal silver is a "jack of all trades," offering a wide range of health benefits, including fighting infections and boosting the immune system. However, there is limited scientific evidence to support many of these claims.