colloidal silver (a colloid consisting of silver particles suspended in liquid) and formulations containing silver salts were used by physicians in the early 20th century, but their use was largely discontinued in the 1940s following the development of safer and effective modern antibiotics. since about 1990, there has been a resurgence of the promotion of colloidal silver as a dietary supplement, marketed with claims of it being an essential mineral supplement, or that it can prevent or treat numerous diseases, such as cancer, diabetes, arthritis, hiv/aids, herpes, and tuberculosis. no medical evidence supports the effectiveness of colloidal silver for any of these claimed indications. silver is not an essential mineral in humans; there is no dietary requirement for silver, and hence, no such thing as a silver "deficiency".