Chloral hydrate is widely used as a sedative or hypnotic, especially in geriatric and pediatric patients. In therapeutic doses blood pressure and respiration are only minimally affected. We describe a 9-year-old boy in whom a life-threatening cardiac arrhythmia dominated the clinical presentation of chloral hydrate intoxication. In spite of its widespread use, the dangers of chloral hydrate overdosage, especially cardiac arrhythmias, are not sufficiently appreciated.