Ferrous Fumarate
C4H2FeO4
Hazardous Substance Databank Number: 7348
Ferrous fumarate is the anhydrous salt formed by combining ferrous iron with fumaric acid and used
as a hematinic (a preparation used to improve the quality of blood). Unfortunately, inorganic iron is
pro-oxidative, stimulating the damaging effects in the body of substances known as free radicals..(1)
There is evidence linking high inorganic iron intake to cardiovascular disease and cancer.  
Excessive iron accumulates in the liver, and may feed bacterial and viral infection.

Iron is found, in a healthy body, in the form of metalloproteins, because in exposed or in free form it
causes production of free radicals that are generally toxic to cells.  In its "free" form iron binds avidly
to virtually all biomolecules so it will adhere nonspecifically to cell membranes, nucleic acids,
proteins etc, causing substantial damage.  When, for instance, iron binds with LDL, it oxidizes it,
resulting in obstruction.

After all, how can something which is the #1 cause of death by poisoning of children under the age
of 6, be safe for ingestion, at any dose?
Wikipedia "Iron
Precautions" Link


(2) Ferrous Fumarate causes oxidative
stress
(1) Ferrous Fumurate Deterioriated
Antioxidant Status in Patients with
Crohn Disease,