Colloidal silver is a considered a general term describing the 'presence' of silver ions, neutral particles, or silver compounds suspended in water or in a fluid. Moreoever, this definition applies to the purpose of using such a fluid for medicinal purposes. The idea being that 'colloidal silver' is a broad term, meaning that there are many forms of silver in colloidal suspension. Some forms are more active than others.

Colloidal silver therefore means any fluid containing silver used for medicinal purposes.

A colloid is technically defined as particles which remain suspended without forming an ionic, or dissolved solution. The broader commercial definition of colloidal silver includes products that contain various concentrations of ionic silver, silver colloids, ionic silver compounds or silver proteins in purified water.

Colloidal silver products consist of microscopic silver particles suspended in liquid base. They are usually marketed as dietary supplements. Sometimes other ingredients are added, such as proteins, coloring, etc. The products are usually taken by mouth (in which case the products are considered dietary supplements). Some other types are sprayed, applied to the skin, or injected into a vein.

Over-the-counter colloidal silver products are not considered by the U.S. Food and Drug Administration (FDA) to be generally recognized as safe and effective for diseases and conditions.

Colloidal silver can cause serious side effects. One is argyria, a bluish-gray discoloration of the body. Argyria is not treatable or reversible.

Silver is a metallic element that is mined as a precious metal. It has various industrial uses, for example, in jewelry, silverware, electronic equipment, dental fillings, photographic processing, and disinfecting water.

People are commonly exposed to silver, usually in tiny amounts, through the environment (such as the air), drinking water, and food, and possibly their work or hobbies. Silver has no known biological function in living organisms.

Silver has had some medicinal uses going back for centuries. However, more modern and less toxic drugs have eliminated most of those uses. A few prescription drugs containing silver are still available.