Organic compound with a complex multi-ring molecule that occurs in the bark of Pacific yew trees ( Taxus brevifolia ).
It is active against certain cancers of the lung, ovary, breast, head, and neck, disrupting cell division and interfering with separation of the nuclear chromosome s. A semisynthetic process to make it from yew needles and twigs eliminated the prospect of widespread destruction of yew forests, and total synthesis methods were later developed.