Taxol. Computer graphic of a molecule of taxol, a promising anti-cancer drug. The atoms are colour- coded: carbon (black); hydrogen (white); oxygen (red); nitrogen (blue). Taxol is found in the bark of the Pacific Yew tree (Taxus brevifolia) and has been found effective against some tumours, notably advanced breast and ovarian cancer. T. brevifolia is an endangered species of tree, so availability of taxol in nature is low. In 1994, scientists succeeded in synthesizing taxol in the laboratory. This was only made possible once the molecular structure of taxol was known.