Poisonous plants

Contains cardiac glycoside toxins¹.  

Clinical signs include:  

• Cardiovascular: changes to heart rate and breathing difficulties 
• Digestive: diarrhoea 
• Neurological: dilated pupils, tremors and fits 

• 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.

• 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).

Contains eight toxic alkaloids. All parts of the plant are poisonous with the seeds containing the highest level of toxins.

Clinical signs include:  

• Dilated pupils
• Lack of coordination
• Tremors or seizures
• Loss of appetite
• Drooling
• Bloating
• Stomach problems and more frequent bowel movements.

• Detection needs to be rapid before too much damage is caused to the horse’s nervous system.
• Vets may use activated charcoal to absorb and flush out the toxins.
• Signs of poisoning will occur within an hour of ingestion.

• Keep horses away from areas of growth. 
• Remove any Hemlock found on your pasture - once pulled do not leave in the field as it remains poisonous in its dried form. 
• Hemlock can be harmful to human skin, so make sure to wear protective clothing when removing. 

• Members of the same family as Hemlock, these plants are found in damp meadows, rivers and near lakes.
• Both have sappy stems which can attract horses in dry weather. The leaves are triangular and lobed and taper down to a point. The stem is green and hollow and has multiple parsnip-like roots.
• Often mistaken for Cow Parsley (which isn’t poisonous to horses). Cow parsley can be identified by its ridged stems similar to celery and a fresh herby smell.
• For prevention follow the same methods as Hemlock. 

Clinical signs of poisoning 

• Dilated pupils
• Lack of coordination
• Tremors or seizures
• Drooling
• Bloating
• Stomach problems and more frequent bowel movements.

Water dropwort 

Cowbane

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 

Death from deadly nightshade intoxication is rare. 

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

Horses rarely eat deadly nightshade as they find it distasteful. 

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

Contains triterpenoid saponins and polyacetylene toxins that harm horses. 

Clinical signs include:  

• Diarrhoea 
• Colic 
• Skin irritation around the mouth 
• Loss of appetite  
• Dehydration 

• Death from ivy poisoning is rare. 
• However, you should contact a vet as soon as you suspect your horse has eaten ivy to treat the symptoms and prevent any further toxin damage.

• Horses rarely eat ivy as they find it distasteful. 
• Keep horses away from areas where ivy grows,  
• Remove any ivy you find.

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 movements¹ 

• Death by taxine poisoning can occur instantly. 
• Contact a vet immediately if you suspect your horse has eaten yew 

• 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. 

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

• 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. 

• 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. 

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/