Nano-silver is silver that has been prepared in such a way that it forms numerous microscopic particles. It is identical to a substance called colloidal silver, in which the tiny nano-scale silver particles are suspended in a liquid to form a solution called a colloid.
Nano-silver is known for its extremely potent antimicrobial properties. However, nano-silver has also been marketed as a quack medication, said to cure everything from cancer to Ebola. While silver does effectively kill pathogens outside the human body, its action within the human body has not been well-researched and remains speculative as of 2015. One known effect on the human body is that it can cause argyria, a discoloration of the skin. This is caused by silver salts building up to excessive levels.