Yew (Taxus species) in Pets

Yew needles and seeds contain taxine alkaloids that can stop the heart suddenly. Learn which parts are toxic, why clippings are dangerous to horses, and what to do now.

What It Is

Yews are evergreen trees and hedges with flat dark needles and red, berry-like cones called arils. The needles, bark and seeds contain taxine alkaloids, which block calcium and sodium channels in the heart and can stop it suddenly. The Merck Veterinary Manual notes that the red fleshy berry itself is not considered poisonous, but the seed inside it is.

Where Pets Come Across It

Churchyards, formal hedges and topiary, park plantings and foundation shrubs. Clippings dumped over a fence are a classic cause of sudden death in horses and cattle; dogs chew sticks and berries.

Which Animals Are Affected

Horses, cattle and other livestock are poisoned most often and are very sensitive. Dogs and cats are also susceptible.

Published Toxic Dose

No owner-usable mg/kg threshold is published for dogs or cats. Toxin content varies by species, season and plant part, and dried clippings stay toxic. Sudden death in large animals has followed small amounts of foliage. The calculator therefore skips the risk grading for yew.

Signs and How Soon They Appear

In large animals the first sign is often sudden death. Dogs and cats may show vomiting, drooling, tremors, wobbliness, breathing difficulty and a slow or irregular heart, sometimes within an hour, then collapse.

What to Do Right Now

Call your vet or poison line immediately, and keep your pet calm because exertion can worsen heart effects. Bring a sprig to confirm identification. Do not induce vomiting at home. Never put yew clippings where animals can reach them.

Identifying yew and the risk to horses and livestock

Yews are dark evergreen conifers with flat, needle-like leaves about 1–3 cm long, glossy dark green above and paler beneath, arranged in two rows along the twig. The 'berries' are red cup-shaped arils with a single dark seed visible at the open end. Common yew (Taxus baccata) is found in churchyards and old hedges in Europe; Japanese and hybrid yews are popular landscaping shrubs in North America. Horses, cattle, sheep and goats are the animals most often killed, typically after eating clippings or reaching over a fence into a garden. Horse owners should check boundaries for yew and make sure neighbours know not to throw cuttings into paddocks. Dried yew in hay or bedding remains dangerous.

Frequently Asked Questions

Sources and References

• Merck Veterinary Manual: Houseplants and Ornamentals Toxic to Animals (yew)
• ASPCA: Yew

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