Methylene iodide poisoning. A 20-month-old girl ingested a maximum of 25 mL of pure methylene iodide. Within two hours, the patient exhibited lethargy and incoordination and vomited. An abdominal radiograph demonstrated the radiopaque material in the gut. In vivo conversion to carbon monoxide was documented with a peak carboxyhemoglobin level of 14.2% reached at 11 hours after ingestion. Two days after ingestion, evidence of hepatotoxicity was apparent, and fulminant hepatic failure quickly ensued. Despite aggressive supportive care and transfer to a liver transplant center, the patient died nine days after ingestion. Methylene iodide ingestion has not been previously reported in human beings. This case verifies that this substance is a potent hepatotoxin, is metabolized to carbon monoxide in vivo, is radiopaque, and may cause bone marrow suppression. 