Pets and Plants:

Yews are small relatively slow growing coniferous trees or shrubs in the family Taxaceae.

Taxus cuspidata (Japanese yew, spreading yew, western yew) is native to Japan, Korea and China, and Taxus baccata (yew, English yew, European yew) is native to Europe – both are widely grown in North America as ornamental plants.

Yews are extremely toxic to all animals including horses, ruminants, dogs and cats. These plants have great potential for toxicity because they are so widely planted an ornamental shrubs or trees, and plant material is readily available to be consumed by animals. The toxic principles are alkaloids named taxine and various volatile oils. The entire plant is toxic but animals usually ingest leaves or berries. Both fresh and dried yew plant material is poisonous. For dogs, twofifths of an ounce of plant material per 10 pounds of body weight is lethal.

Clinical signs include trembling, weakness, heart or breath- ing problems, vomiting, seizures (dogs) and frequently, sudden death with no other signs. Death is due to sudden heart failure and/ or respiratory collapse. Treatment includes oral decontamination and supportive care.

Of related interest is use of compounds from yew for medical purposes. Paclitaxel (Taxol) is a compound used for cancer chemotherapy (ovarian, breast, lung cancer) and isolated in 1967 from the bark of the Pacific yew tree (Taxus brevifolia). Later it was discovered that endophytic fungi in the tree bark synthesize paclitaxel. From 1967 to 1993, almost all paclitaxel was derived from Pacific yew bark – the harvesting process killed the tree. Currently, all paclitaxel production uses plant cell fermentation technology and does not require harvest of trees.

Yews are widespread ornamental trees and shrubs. Yew plant material is very toxic to all animals and care should be taken to prevent animal exposure to these materials.