Iron toxicity is one of the most common causes of pediatric poisoning deaths, occurring from accidental ingestion of iron-containing supplements and prenatal vitamins. Elemental iron is directly corrosive to GI mucosa, causing hemorrhagic gastroenteritis in the first phase (0-6 hours). Free iron exceeding transferrin binding capacity generates hydroxyl free radicals through Fenton reactions, causing lipid peroxidation, mitochondrial damage, and cellular necrosis. Iron toxicity progresses through five phases: GI phase (0-6 hours with vomiting, diarrhea, abdominal pain, hematemesis), relative stability (6-24 hours, falsely reassuring), systemic toxicity (12-48 hours with shock, metabolic acidosis, hepatotoxicity, coagulopathy), hepatotoxicity (2-3 days), and late GI stricture formation (2-8 weeks). Serum iron > 500 mcg/dL indicates severe toxicity. Deferoxamine chelation is the specific antidote, binding free iron for renal excretion.