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Ferrous Oxide

Medically reviewed by Last updated on Jun 15, 2023.

Excipient (pharmacologically inactive substance)

What is it?

Ferrous oxide (FeO), or iron (II) oxide, is an iron oxide and exists as a black powder. It is not rust (ferric oxide). Iron(II) oxide makes up part of the earth's mantle. Synthetic iron oxide is approved for used as a pigment in certain foods, cosmetics, contact lenses and drugs.[1][2]

List of medications using Ferrous Oxide


  1. [1] Ingredient Glossary - iron oxides. Accessed March 30, 2014.
  2. FDA. For Industry. Summary of Color Additives for Use in the United States in Foods, Drugs, Cosmetics, and Medical Devices. Accessed April 1, 2014.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.