Can they eat it? / Yew (Taxus)
Can horses eat yew (taxus)?
Never. A mouthful can stop the heart within hours.
Every part is poisonous, and clippings thrown over a fence are the classic cause. There is no safe amount and often no warning. Check hedges along fence lines and never let garden waste near a paddock.
Trembling, difficulty breathing, collapse, sudden death.
Call your vet now. Note what was eaten, how much and when; do not wait for signs.
Why it is dangerous
Yew contains taxine alkaloids, which block the heart's ability to regulate calcium and electrical signals, so the heart can slow, stop or beat erratically. Every part of the plant carries these compounds, and the needles and seeds are concentrated sources. Horses are sensitive because they often eat clippings casually, and the toxin does not change when the leaves dry or wilt, so hay or trimmings can be just as dangerous as fresh branches.
How much is too much
For a 1,000 lb horse there is no safe amount of yew. A few needles, a small handful of clippings or a single branch can be enough to cause serious heart trouble, and a larger portion can be fatal within hours. Ponies, miniatures and very small horses need even less. Because a horse may eat only a little and show no early signs, treat any exposure as an emergency regardless of size or quantity.
Horses
For horses in work or turned out on pasture, the main risk is hedge trimmings, prunings and garden waste that get tossed over a fence or left near a paddock. Walk fence lines and remove any yew branches that overhang the boundary. Keep wheelbarrows, compost piles and clipping bins well away from grazing areas, and check hay carefully, since yew can be baled in with grass.
Ponies and easy keepers
Ponies, miniatures, seniors and easy keepers can be just as vulnerable, and smaller bodies mean a smaller dose can do damage. Because these horses are often turned out in small paddocks with more time to browse, yew hedges along the boundary are a particular concern. Keep yew entirely out of reach, check any new pasture or paddock before turnout, and never assume a pony is too picky to try it.
Safe alternatives
Offer safe browse such as a fresh flake of grass hay, a timothy or orchard grass bale, or a grazing muzzle on a rich pasture. For enrichment, provide a hay net or a salt block placed where yew cannot reach. If a treat is wanted, a small piece of carrot or a few horse-safe pellets works well and keeps attention away from the fence line.
Questions people ask
Is yew safe in hay?
No. Yew stays toxic when dried and baled, so it should never be fed as hay or allowed into a hay field. Check hay carefully and remove any yew before feeding.
What should I do if my horse ate yew?
Call your veterinarian right away, even if your horse looks fine. Note what was eaten, roughly how much, and when it happened, and do not wait for symptoms to appear.
Can a horse have yew after a frost?
No. Frost and cold do not reduce yew toxicity, and wilted or dried clippings remain dangerous. Keep all yew clippings away from horses in every season.
Toxic for horses means: do not give it; if they ate it, call your vet or a poison line.
General information from veterinary guidance, not a diagnosis. If you are worried, call your vet or a pet poison line: ASPCA Animal Poison Control (888) 426-4435. Charges may apply.
Written by Hoofdeck editors · updated Nov 13, 2026 · from ASPCA Animal Poison Control, Merck Veterinary Manual and university extension guidance.