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May 3, 2011


10 most toxic plants to horses

by DePaolo Equine Concepts

As spring heads to summer it is a good time for horse owners to get a little refresher course on poisonous plants. Some plants are poisonous when they are thriving or in blossom while some are most poisonous when they have died and are already dried out.  Leaves, roots, flowers and roots can all be poisonous depending on the plant.  Or in some cases all of the plant can be deadly.

Very toxic plants such as oleander (above) and yew (below)

can kill a horse in less than 10 minutes.  Some are slow to affect the horse such as certain types of ferns and the negative side effects may not even be noticed for several weeks or months after ingestion.


The black walnut tree (above) is not toxic when eaten but rather when the walnut pods fall of the tree, die and come in contact with your horse’s feet.  It can cause laminitis which isn’t usually associated with toxicities.  It is very important to make sure your shavings/bedding doesn’t contain any black walnut because shavings that have 10% black walnut have been knows to cause laminitis.

The good news is that most of the time a horse’s instincts keep them away from toxic plants.   Most toxic plants are unpalatable to horses but in a few cases, such as with star thistle, a horse can actually develop a taste for it.

If you suspect your horse has digested a toxic plant call your veterinarian immediately.  You will most likely have to put the horse through a detoxification program and in some cases you may need IV fluids or medication.

2 Comments Post a comment
  1. Jennifer Zander
    Jul 1 2011

    My horse recovered this year from a horrible toxicity to Creeping Charlie that has become a nasty invasive species in the NW and all over most of the US. After having to put my horse on heavy steroids just to alleviate the affects from the ultimate hives that broke out over her entire body, she needed additional supplementation to detoxify and rebuild her immune system. Thankfully, Dr. DePaolo suggested Chvel. Withing a week my mare responded and began to be her old self again.
    Unfortunately, I have to be very careful where I graze her, because she has taken a liking to the CC. We Weedmastered all pastures and hand-pulled the CC before I was able to turn her out again.
    I suggest everyone make an effort to get rid of CC on their property; horses will eventually nibble on it.
    It affects the respiratory system. Symptoms are excitability, excessive drooling, eyes dilate and elevated respiration (She never had a high temp). My horse exhibited all of these symptoms, but then, also broke out in the horrible blister hives and then her limbs swelled to twice their size. There have been reported deaths of this in years past.
    I hope no other horse has to go through this.
    JZ in OR


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  1. 10 most toxic plants to horses | DEC blog | Horse Book Reviews

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