The piperidine phenothiazine thioridazine has been in use for 40 years. As clinical experience has accumulated, scattered reports of sudden death and fatal or nonfatal arrhythmias during routine therapeutic use have been published. This paper reviews the case reports and retrospective studies that have been published to date. Four new case reports in which thioridazine in standard therapeutic doses is implicated as the cause of death or as contributing to the cause of death are presented. The author concludes that the accumulated clinical experience of thioridazine's potential for cardiotoxicity coupled with the availability of alternative, safer antipsychotic medications shifts the risk/benefit equation away from justifying widespread use.