In nature, iron is usually found in its oxidized form, ferric oxide, which is insoluble and therefore non-toxic. Ferrous iron is soluble and highly toxic.
Symptoms
The first indication of iron poisoning by ingestion is a pain in the stomach, as the stomach lining becomes ulcerated. This is accompanied by nausea and vomiting. The pain then abates for 24 hours as the iron passes deeper into the body and damages internal organs, particularly the brain and the liver. The body goes into shock and death from liver failure can result.