The study reports a case of suicide by ingestion of sodium nitroprusside which resulted in acute cyanide poisoning. Analyses carried out on body fluid yielded the quantitation of total (5.00 mg/L) and free (3.30 mg/L) cyanide in blood and of methemoglobin (blood = 10.5%). At the scene, some solid reddish-brown material was found in a glass, which on toxicological analysis was found to contain sodium nitroprusside; about 9 g of the same substance was identified in stomach contents. The detection and quantification of cyanide and methemoglobin in biological samples from the case indicated that the lethal effect was due to both metabolic products (cyanide and methemoglobin).