While hospitalized, a 3-year-old girl went into coma on four separate occasions. Neurologic evaluation of this patient suggested a toxic encephalopathy. Following exhaustive pharmacologic investigation, toxic quantities of chloral hydrate were isolated from the child's blood, urine, and gastric contents. It was discovered that the child's mother had tried to poison her daughter with the drug. This unusual case demonstrates the value of perseverance in the clarification of an ill-defined clinical problem.