The toxicologic findings in a case of fatal poisoning with verapamil (Isoptin) are are presented. For isolation of verapamil the biologic material was subjected to protein precipitation. The aqueous solutions were acidified with hydrochloric acid, prepurified by extraction with ether, and subsequently the basic drug verapamil was isolated by ion pair extraction with chloroform. Quantitative determination of verapamil was carried out by gas chromatography using a nitrogen specific flame ionization detector. The following concentrations of verapamil were measured: liver 5500 ng/g, kidney 2000 ng/g, blood 590 ng/g, urine 250 ng/g, gastric contents 3 mg (total). During examination by the police it was claimed by a witness that two tablets of Isoptin had been taken before death. After application of a therapeutic dose of Isoptin peak concentrations of 11 and 30 ng/g of blood cells and of 30 and 65 ng/g of plasma were measured in two healthy subjects; the latter figures corresponded well to previous findings of other authors, who investigated plasma concentrations of verapamil after therapeutic administration. In the case presented here, the blood concentration of 590 ng/g clearly demonstrated that an extreme overdose must have been taken before death.