A 42-year-old woman had an accidental overdose of chloral hydrate due to repeated absorption of a therapeutic dose of chloral syrup for insomnia. The total ingestion was estimated at 8 g. Overnight slight loss of consciousness associated with severe cardiac arrhythmia (bigeminia ventricular extra-systole) needed admission to the intensive care unit and intravenous lignocaine for two days. The evolution was satisfactory.