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Poisonous plants

There are many plants, shrubs, hedges, and trees poisonous to horses. You need to be aware of what plants are unsafe for your horse so that you can regularly check for and remove them.  

  • Last reviewed: 14th July 2022
Forest Setting with Ivy Forest Setting with Ivy

Poisonous plants to horses

Remember, it’s best to wear gloves when handling poisonous plants. 

It is also good to note that often poisonous plants thrive on poor quality land, making it even more important to maintain good pasture.  

Foxglove

  • Grow up to 2 meters tall
  • Flowers are purple-pink, hanging, tubular structures which are 4-5 cm long
  • Flowers appear from June to September
Toxin and clinical signs of poisoning

Contains cardiac glycoside toxins1.  

Clinical signs include:  

  • Cardiovascular: changes to heart rate and breathing difficulties 
  • Digestive: diarrhoea 
  • Neurological: dilated pupils, tremors and fits 
Prognosis and treatment
  • Death from foxglove poisoning can occur after just a few hours1.
  • Contact a vet as soon as you suspect foxglove poisoning.
  • If caught early enough, a vet may use activated charcoal and mineral oil to flush out the toxins1
  • Treatment options are limited as the toxins can immediately damage a horse’s cardiovascular system.
Prevention
  • Ensure good forage is available as horses don’t usually eat foxglove unless other food is unavailable.  
  • Keep horses away from areas of foxglove growth. 
  • Remove any foxglove found on your pasture immediately (it’s important to note that toxicity remains even when the plant is dried and dead1).
41 Foxglove
Foxglove

Deadly Nightshade

  • Grow up to 1.5 meters high 
  • The leaves can grow up to 20cm long 
  • The flowers are most often a dull brown-purple colour and grow up to 3 cm long 
  • The fruit is a shining black berry
Toxin and clinical signs of poisoning

Contains atropine alkaloids, present in all parts of the plant especially stems and leaves1.

Clinical signs include:  

  • Dilated pupils and blindness 
  • Changes to heartbeat 
  • Muscle tremors 
  • Disorientation 
Prognosis and treatment

Death from deadly nightshade intoxication is rare. 

However, you should always call a vet for supportive treatment. 

Prevention

Horses rarely eat deadly nightshade as they find it distasteful. 

Remove any deadly nightshade found by pulling or digging it up.

42 Deadly Nightshade
Deadly Nightshade

Ivy

  • Leaves are dark green and often triangle-shaped 
  • Grows in vines
Toxin and clinical signs of poisoning

Contains triterpenoid saponins and polyacetylene toxins that harm horses. 

Clinical signs include:  

  • Diarrhoea 
  • Colic 
  • Skin irritation around the mouth 
  • Loss of appetite  
  • Dehydration 
Prognosis and treatment
  • Death from ivy poisoning is rare. 
  • However, you should contact a vet as soon asyou suspect your horse has eaten ivy to treat the symptoms and prevent any further toxin damage.
Prevention
  • Horses rarely eat ivy as they find it distasteful. 
  • Keep horses away from areas where ivy grows,  
  • Remove any ivy you find.
Ivy
Ivy

Yew Trees

  • Are evergreen trees or bushes, growing up to 20 meters 
  • The thick trunk is a red-brown colour with scaly and peeling bark 
  • Leaves are dark green, typically 1-3 cm long and needle-shaped 
  • Young leaves are bright green 
  • Often have red berries
Toxin and clinical signs of poisoning

Yew contains the deadly toxin Taxine, a cardiotoxin that causes a heart attack1.  

Clinical signs include:  

  • Sudden collapse is sometimes the only sign  
  • Breathing may begin to sound like groaning 

Neurological: muscular trembling and uncoordinated movements

Prognosis and treatment
  • Death by taxine poisoning can occur instantly. 
  • Contact a vet immediately if you suspect your horse has eaten yew 
Prevention
  • Yew tastes bitter and horses don’t usually eat it unless other forage is in short supply, such as in winter.
  • Keep your horse well away from any yew plants. 
  • Be aware that toxicity remains in clippings and dead plants1
43 Yew
Yew

Laburnum

  • Usually grow to 7-8 meters 
  • The bark is smooth and a grey or olive-green colour. 
  • Produces bright yellow drooping flowers 
Toxin and clinical signs of poisoning

Contains the toxin Cytisine, present in all parts of the plant, but especially the seeds2

  • Digestive: colic and diarrhoea 
  • Neurological: drowsiness, excessive salivation, fitting, collapse and coma2
Prognosis and treatment
  • Contact your vet immediately for supportive treatment If you suspect your horse has eaten laburnum.
  • Your vet may use activated charcoal, liquid paraffin and fluids to flush the toxin out2
Prevention
  • Horses don’t usually eat laburnum, unless they are short of other forage, as it tastes bitter. 
  • Keep your horses away from areas where Laburnum trees grow or fence off the area around the trees to avoid access to it. 
45 Laburnum
Laburnum

References
  1. Cheltenham Equine Vets. 2018. Plants Poisonous to Horses. Available from: https://cheltenhamequinevets.co.uk/wp-content/uploads/2018/02/Plants-poisonous-to-horses.pdf
  2. Simon Constable’s Equine Vets. Laburnum Poisoning. Available from: https://equine-vets.com/health/l/laburnum-poisoning/ 

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