A fatal case of intentional oral cyanide poisoning in a tetraplegic patient whose repeated legal requests to be allowed to perform euthanasia had been refused, is reported. The postmortem provided no specific findings and the diagnosis was based on the toxicological analysis of the different samples available. Cyanide was determined in all biological (blood, vitreous humour, bile, urine and viscera) and non-biological samples received (liquid found in a glass beside the body in the scene of the crime). The high cyanide concentrations in blood (21.5 mg/L) are consistent with death through cyanide poisoning. Also, the cyanide concentration in the water held in the glass from which the casualty presumably drank 81900 mg/L), and the high levels of potassium ion found (186 mEq/L), allowed us to conclude that the death was due to the intake of an amount of potassium cyanide between 500 and 1000 mg.

        Key words: forensic toxicology - potassium cyanide - poisoning - suicide