Taxus baccata is a widely distributed yew often associated with cases of fatal intoxication, which is related to the high amounts of cardiotoxic alkaloids, taxine A and taxine B, contained in its leaves. In this paper, a case of Taxus fatal poisoning, hypothesized by the forensic autopsy, has been confirmed by the application of both gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS-MS) techniques. A GC-MS method was used for the determination of the derivatized 3,5-dimethoxyphenol, a cyanogenic aglylactone considered as a marker of Taxus poisoning, being present in all species of Taxus. The detection by LC-MS-MS of taxine B and isotaxine B in the biological specimens confirmed the absorption of cardiotoxic alkaloids and allowed to established the cause of death as the ingestion of Taxus baccata leaves.