This report describes the occurrence of generalised seizures in a 42-year-old woman who presented to hospital after deliberate lamotrigine overdose. Seizure activity was promptly terminated after intravenous benzodiazepine administration, and the patient subsequently made a complete recovery. Serum lamotrigine concentration was 30 mg/l at 1.3 h post-ingestion, which is substantially higher than the therapeutic reference range; the estimated elimination half life was 18.3 h. This case reminds us that lamotrigine toxicity may provoke generalised seizures in susceptible individuals.