The Common Yew (Taxus baccata) contains at least 10 different alkaloids that are contained in yew berries, needles, or bark. Of these, which alkaloid is the most active cardiotoxin?
Taxine B. The major taxine alkaloids are taxine A and taxine B, and taxine B is responsible for the greatest cardiac toxicity.
Ondřej Piskač, Jan Stříbrný, Hana Rakovcová, et al. Cardiotoxicity of yew. Cor et Vasa. 2015 June 57;3:e234-e238. https://doi.org/10.1016/j.crvasa.2014.11.003