Which Sycamore Trees Are Poisonous to Horses?

You may have heard rumors about certain trees being poisonous for horses–sycamore trees in particular. Now, you want the facts. Which sycamore trees are poisonous for horses? Which ones are harmless? As a horse owner, are there any other trees you should be concerned about on your property? Read on for answers to all of these questions.

Are Sycamore Trees Poisonous to Horses?

Are Sycamore Trees Poisonous to Horses?

In short, the answer to this question is no; true sycamore trees are harmless to horses and do not cause poisoning. However, this answer is not as simple as it might seem and is somewhat dependent on where you live.

There are many types of trees in the world with “sycamore” in their common name. However, they are not all related; they belong to various plant families, and most are not true sycamores.

Some of these trees are poisonous to horses, causing an often-deadly muscle disease called atypical myopathy. This disease causes muscle damage which can lead to problems with standing, moving, and breathing, as well as heart damage.

However, true sycamore trees do not cause this reaction, and many species of tree bearing the sycamore name are perfectly harmless to horses.

The most dangerous trees with sycamore in their name are found growing throughout Europe and parts of Asia. Horses may be poisoned if they eat the seeds or saplings of these trees.

Find out how to prevent atypical myopathy by checking out the following video:

Which Sycamore Trees Can Poison Horses?

As noted, there are several different genera of trees with sycamore in their name. These include:

  • Platanus
  • Acer
  • Ficus
  • Cryptocarya
  • Ceratopetalum

For the purpose of this article, we will be focusing on trees in the Platanus and Acer genera.

Trees in the Platanus genus may be considered “true sycamores,” at least in North America. This genus contains trees native to North America such as the American sycamore, the California sycamore, and the Arizona sycamore.

Sycamore trees belonging to the Platanus genus are not harmful to horses. They do not contain the chemical compounds responsible for causing atypical myopathy.

Trees belonging to the Acer genus, on the other hand, are highly toxic to horses.

Acer pseudoplatanus, the sycamore maple, is a common tree found throughout Europe and Asia. In its native range, it is known simply as “sycamore.”

This tree is not a true sycamore, but it is the one responsible for giving sycamores a bad name among horse lovers. Its leaves and seeds contain toxins known as MCPG and hypoglycin A, which are responsible for causing atypical myopathy.

American Sycamore vs. Sycamore Maple

The American sycamore, Platanus occidentalis, is found growing widespread throughout the United States and other parts of North America. 

Meanwhile, the sycamore maple, Acer pseudoplatanus, grows in Europe and Asia. It does not grow natively in North America.

These two trees may be confused because they are both simply called “sycamore trees” by the natives in their respective ranges. 

However, despite similarities in appearance, they are not found growing in the same places, and they are not the same type of tree.

Therefore, those living in the U.S. or other parts of North America don’t need to worry about their horses being poisoned by sycamore trees. The types of sycamores growing in North America are harmless to horses.

On the other hand, people native to the U.K. or other parts of Europe and Asia should take care to keep sycamore trees and seeds away from their horses’ pastures. The sycamore trees growing in these regions are highly poisonous to horses and may even cause death if their seeds or seedlings are ingested.

Other Trees That Can Poison Horses

Other trees belonging to the Acer genus should be kept away from your horses. They do not all cause atypical myopathy, but they can all cause poisoning and death.

Trees in the Acer family include maples and boxelders, which can be found throughout much of the world, including North America. If you have horses, be on the lookout for these trees regardless of where you live.

Other trees to keep away from your horses include:

  • Oaks
  • Black walnuts
  • Buckeyes/horse chestnuts
  • Chokecherry
  • Black locust


The sycamore trees growing in North America are not poisonous to horses; however, those growing in Europe and Asia can cause a deadly muscle disease called atypical myopathy. Other trees that are poisonous to horses include oak trees, choke cherry trees, and horse chestnut trees.

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