A 2-year-old girl presented with vomiting and diarrhea 7 hours after eating a large quantity of ginkgo seeds. She exhibited an afebrile convulsion 9 hours after ingestion. The serum concentration of 4-metoxypyridoxine was as high as 360 ng/mL. Although reported cases of ginkgo seed poisoning usually involve children who exhibit repetitive seizures that can be fatal, prompt administration of pyridoxal phosphate (2 mg/kg) may have prevented additional seizures. This is the first English-language case report measuring 4-metoxypyridoxine concentration during ginkgo seed poisoning. Awareness of the potential danger of overconsumption of this traditional food and its prompt treatment with pyridoxal phosphate may hasten recovery.