Acute lithium intoxication is potentially lethal. Compared to conventional lithium preparations, sustained-release lithium formulations present specific problems for medical practice in the case of overdose. We report a case of intoxication with 8000 mg of sustained-release lithium carbonate preparation (Teralithe 400 LP®). Twenty-five hours after the ingestion, the patient was still asymptomatic, despite a serum level in the toxic range. After comparison of this case with reports found in the Medline database, we consider the clinical management of such cases.