Trazodone has been available for approximately 30 years and has a reputation as a safe drug. The normal upper therapeutic blood concentration for trazodone is about 2 milligrams per liter, fatalities are rarely attributed solely to it at blood concentrations below 9 milligrams per liter. However, potential interactions between other drugs with serotonin reuptake properties need consideration, as does the increased susceptibility to the toxic effects in individuals with pre-existing heart disease. The analysis of these 37 cases revealed that none were attributed solely to trazodone, although trazodone was often present with other serotonergic drugs such as selective serotonin reuptake inhibitors like fluoxetine and sertraline. Ten cases had blood trazodone concentrations above 2 milligrams per liter. Trazodone had a primary role in the death of three individuals in which blood concentrations were all greater than 9 milligrams per liter. Findings confirmed the conclusions of others that trazodone is a relatively safe drug except in massive overdose, although the presence of other drugs and underlying pathophysiology may influence its toxicity. Tables and 40 references (Author abstract modified)