The paper reviews the complex pharmacology of the new class of antidepressant medications exhibiting selective inhibition of serotonin reuptake. The four selective serotonin reuptake inhibitors (SSRIs) considered--fluoxetine, fluvoxamine, sertraline and paroxetine--can result in toxicity and death through contributing to serotonergic excess resulting in serotonin syndrome, inhibiting the metabolism of other centrally acting drugs, leading to accumulation of toxic concentrations and exerting complex vasoactive effects on the vascular smooth muscle. This latter feature is of particular concern to patients with preexisting heart disease. The article describes an analytical method involving isolation of the drugs by liquid/liquid extraction at alkaline pH into n-butyl chloride and analysis by gas chromatography/mass spectrometry, together with some of its limitations. Toxicologic and cause and manner of death data were examined in 168 cases involving the four SSRIs. Deaths involving drug toxicity were generally a result of ingesting multiple drugs; in only a small number of cases was death attributed principally to the SSRI involved. The article discusses the potential for interactions between or among members of this class of drugs as well as their metabolites and a variety of other therapeutic and abused drugs which can contribute to their toxicity. Tables, figure, references