There is limited published data concerning carbonyl iron ingestion and no data on overdose. A retrospective chart review of all patients with carbonyl iron ingestion reported to 5 regional poison information centers from January 1998 to April 2000 was done. Thirty-three patients with carbonyl iron ingestion were reported. Twenty-seven patients (82%) were managed without referral to a health care facility. The mean and median age of these patients was 3years and 20 months, respectively. The mean dose ingested was 11.2 mg/kg (range of 2.2 to 34.5 mg/kg) with no effects noted. Six patients evaluated in the emergency ingested a mean of 34 mg/kg (range of 12 to 72 mg/kg). The mean peak serum iron concentrations in 4/6 were 82 microg/dL (range of 36 to 177 microg/dL). One child with a history of flu-like symptoms reported diarrhea, fever and lethargy and had a serum iron concentration of 36 microg/dL; symptoms were believed unrelated to the exposure. In this limited first case series of iron carbonyl ingestion, serious toxicity did not occur.