A semi-quantitative LC-MS method was developed for the detection of the pseudo alkaloids of Taxus baccata (yew) from human body fluids and tissue samples. This method was used to examine the cause of death of a 43-year-old man who died several hours after he drank a decoction of taxus leaves. Autopsy and histology demonstrated early signs of myocardial hypoxia. Since investigation of the stomach content did not yield evidence of taxus ingestion, the taxus alkaloids were determined in blood, stomach content and tissue samples of the deceased by LC-MS. The samples were prepared by solid phase extraction on RP-18 columns. Chromatographic separation was achieved by HPLC on a RP-8 column, coupled to an ion trap mass spectrometer (Finnigan LCQ). An atmospheric pressure electrospray ionisation was performed. Spectra of the alkaloids were recorded in the single MS mode and in the MS-MS mode and compared with reference spectra obtained from an extract of yew leaves. In the stomach content, the kidneys, the liver and a heart blood sample of the deceased, alkaloids of Taxus baccata, predominantly taxine B and iso-taxine B, were identified. The semi-quantitative evaluation of the heart blood revealed a taxine concentration of 11 micro g taxine/g. As far as we know this is the first case in which a semi-quantitative analysis of taxine alkaloids has been performed.