Silver has been prized for thousands of years as a purifying agent and medicine. The ancient Greek historian Herodotus wrote that Persian kings would only drink water that was transported in silver containers which kept it fresh. In the 1500s, Paracelsus, a Swiss physician, began applying it to wounds and giving it to patients orally. Other doctors followed suit. In the 1880s, German obstetrician Carl Siegmund Franz Crede started treating newborn infants with eye drops containing a silver solution to protect them from being blinded by gonorrheal ophthalmia. The following decade, a surgeon named B.C. Crede started using colloidal silver — water with silver particles suspended in it — to keep wounds from being infected [source: Alexander].
The use of silver as an antimicrobial agent continued into the 1900s. Surgeons used silver foil for wound dressings, and they often closed incisions with silver sutures [source: Alexander].
While the advent of antibiotics diminished silver's role, the metal actually is an effective bacteria killer. Silver ions, modern research reveals, attack the microbes' membranes, punching holes in them and wreaking more havoc inside by binding to essential cell components such as DNA. In one test, silver killed more than 99.99 percent of the microbes in the sample. While silver is generally safe, it can cause upset stomach, convulsions or even death in high doses [source: Conover].