Horse chestnut toxicity

Attention! This is a potentially life-threatening condition for your horse. Time is of the essence, contact your veterinarian immediately.Find a Vet

Horse Chestnut Toxicity

Horse chestnut (Aesculus hippocastanum) is a tree in which can be toxic to horses if parts are ingested. Horse chestnut trees are often found in urban and rural areas as ornamental and shade trees.
horse chestnut tree horses

Horse chestnut trees are affected by pollution and as a result, in areas polluted by heavy metals its roots will become colonized by fungal endophytes. The tree can grow to heights exceeding 100 feet. The fruit produced is horse chestnuts--which are covered with a brown husk and hair-like spines which remain until the fruit ripens and splits open. The flowers bloom in late spring and appear as long green catkins which have a strong odor. In the fall the leaves turn bright yellow, gold and brown before dropping.


Red mucous membranes
Muscle tremors


  • History
  • Clinical signs
  • Physical exam
  • Laboratory tests



Activated charcoal(1 to 2g/kg orally)
Supportive careIV fluids, analgesics, etc.


  • Make yourself aware of the weeds and plant species that can be invasive in pastures and/or poisonous to horses.
  • Take periodic walks around pastures to check for the presence of potentially poisonous plants
  • Check that hay does not contain dried up poisonous plants
  • If you borrow or hire farm machinery ensure it is clean prior to arriving on your property, the same goes for lending of your own equipment.
  • Quarantine new animals in a separate paddock the first 10 days to 2 weeks after arrival. Weed seeds can be passed through an animal's digestive tract.



Scientific Research

General Overviews

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Risk Factors

  • Letting horses graze in pastures containing horse chestnut trees