Heavy metal ions such as those of arsenic, silver, mercury, and copper exhibit oligodynamic activity, binding to the sulfur atoms in the amino acid cysteine, causing the protein to denature or change its shape and block the active site.

These compounds are low-level bacteriostatic and fungistatic agents, generally not used since other more effective agents are available.

Examples of heavy metal containing compounds used in microbial control include:

Silver nitrate - 1% solution used as a prophylactic treatment against neonatorum opthamalia (infection of the newborn eye by Neisseria gonorrhoeae.

Thimeriosal - a mercury containing compound added to vaccines and contact lens solutions.

Mercurochrome - an organic-mercury tincture used as a topical antiseptic.

Copper sulfate - used as an algicide in pools, reservoirs and fountains.

Zinc chloride - used in mouthwashes and toothpastes.

Zinc oxide - used in baby rash ointments and in paint as a fungicide.