Iron(II) fumarate

Iron(II) fumarate, also known as ferrous fumarate, is the iron(II) salt of fumaric acid, occurring as a reddish-orange powder, used to supplement iron intake. It has the chemical formula C4H2FeO4. Pure ferrous fumarate has an iron content of 32.87%, therefore one tablet of 300 mg iron fumarate will contain 98.6 mg of iron (548% Daily Value based on 18 mg RDI).

Iron supplement
Ferrous fumarate is often taken orally as an iron supplement to treat or prevent iron deficiency anemia. Mixtures of ferrous fumarate and potassium iodate, "double fortified salt", are used to address both iron and iodine deficiencies.