Pacific yew
In 1958, the National Cancer Institute commissioned a study of over 30,000
plant species in hopes of discovering cancer-fighting compounds. Scientists
found one in the bark of the Pacific yew, a conifer native to the Pacific
Northwest. Yet it took extractions from six Pacific yews to yield enough of the
anti-tumor compound paclitaxel for a single patient. Eventually, researchers
learned how to convert a compound from the tree's needles into paclitaxel,
which doctors now use to treat lung, breast, and other cancers.