Top Eight Plants That Are Poisonous For Horses – What You Need To Know

We love our horses and want to keep them safe; each horse is different, but we do all we can to make sure they have the right equipment, have regular vet and farrier checks, as well as eating as healthy a diet as possible.

But some things are out of our control, such as trees, weeds and plants that grow outside that could be poisonous for horses, and maybe even fatal, so we’ve put together a list of the top eight poisonous plants for horses with some tips on where they are most likely to grow, including advice on how to recognise them.


flowering foxglove plant which is poisonous to horses

Where – the foxglove grows throughout Britain from June to September, in woodland areas and hillsides, particularly in acidic soil.

Appearance – they can grow to 2m tall with a long, thin stem. They have tubular, bell-like flowers that are purplish-pink.

Symptoms – these include an abnormal heart rate and breathing difficulties, dilated pupils, fits, vomiting and diarrhoea.

Treatment – death can happen within hours, so it needs to be caught early. Your vet might use activated charcoal and mineral oil to flush out any toxins.

Deadly Nightshade

deadly night shade leaves and berries which is poisonous to horses

Where – Deadly nightshade is quite common and can be found in woodland and scrub areas.

Appearance – it can grow up to 1.5m high, with leaves of up to 20cm. The flowers are a dull purplish-brown and it has shiny black berries.

Symptoms – these include dilated pupils, an irregular heartbeat, muscle tremors and disorientation.

Treatment – Deadly Nightshade is only fatal if it’s consumed in large quantities, but always contact a vet if you think your horse has eaten some.


green and yellow ivy which is poisonous to horses

Where – Ivy is quite common in the British Isles and can be found on woodland, scrub, wasteland, and even on trees.

Appearance – Ivy grows in vines and has quite distinctive, almost triangle-shaped, dark green leaves.

Symptoms – it contains toxins that can cause diarrhoea, colic, loss of appetite, dehydration, and skin irritation.

Treatment – Death from ivy poisoning is rare, as horses don’t find the taste pleasant, but you should contact a vet immediately if you think your horse has eaten some.


A flowering yew which is poisonous to horses

Where – Yew trees are native to Britain and are often associated with churchyards and hedgerows. They are predominantly found in the South.

Appearance – These trees can grow up to 20 m high and have a brown, scaly bark. The Yew tree has dark green leaves and can sometimes produce red berries.

Symptoms – Yews contain a toxin, Taxine, that can cause a heart attack; often the first sign that anything is wrong is a sudden collapse, although there may also be some muscle trembling before.

Treatment –Yew trees can be one of the most poisonous plants for horses and death can be instant, but a vet should be contacted immediately so that the stomach contents can be removed as soon as possible.


a flowering laburnum plant which is poisonous to horses

Where – these can be found throughout the UK and can be found both in gardens and out in the wild.

Appearance – they can grow to 7 or 8m tall. The bark is smooth and grey, and it has drooping, yellow flowers.

Symptoms – it contains a toxin called Cytisine which is mainly present in the seeds, although any part of the plants can contain it. It can cause colic, diarrhoea, and drowsiness.

Treatment – contact your vet immediately as they may need to administer activated charcoal, liquid paraffin, and fluids to flush out any toxins.


a flowering ragwort plant which is poisonous to horses

Where – this is pretty common throughout the British Isles and can be found by roads, on wasteland and in pastures. Because it’s so widespread, it’s considered one of the most common causes of plant poisoning of horses in the country.

Appearance – it has green, frilly leaves and yellow, star-shaped flowers.

Symptoms – Ragwort attacks the horse’s liver. An early sign is weight loss, even though they might be eating normally, and if not treated the horse could go blind and even collapse.

Treatment – due to the bitter taste, horses don’t often eat Ragwort, but they will eat it when dried and fed in hay. There is no specific treatment, but a vet should be called as soon as you suspect your horse has eaten some. Landowners are prohibited from allowing ragwort to grow on grazing land, and there’s a code of practice for preventing the spread, but horse owners should still be vigilant.


a sycamore tree which is poisonous to horses

Where – typically found in woodland, Sycamore trees grow all over Britain.

Appearance – they can grow up to 35m high and have a dark pink-grey bark. The flowers are quite distinctive, often referred to as ‘helicopters’. Sycamore poisoning is more of an issue in the autumn, when seeds are blown off the trees and the concentration of the toxin HGA is higher.

Symptoms – include lethargy, sweating, muscle stiffness and an increased heart rate. The affected horse can often be found lying down.

Treatment – if you think your horse has eaten sycamore seeds you need to contact a vet at once. Treatment includes pain relief and intravenous fluids. Studies show that as little as 50 seeds could be fatal, depending on the type of horse and the level of toxins in the seeds.


An oak tree branch with acorns, which are poisonous to horses

Where – Oak trees are the most common species of tree in the UK, so are widespread throughout the country.

Appearance – they can grow up to 40m high and have green, leathery leaves. They produce acorns in the autumn months.

Symptoms – signs to look out for are constipation, weight loss and blood in the urine. It’s also worth looking for acorn kernels in the faeces if you think your horse has eaten some.

Treatment – this depends on the number of acorns consumed. Your vet may administer intravenous fluids to flush out any toxins, or activated charcoal.


  • Make sure your horse has plenty of forage
  • Fence off trees and plants that are poisonous for horses, or move your horse somewhere else
  • Keep the ground clear of fallen fruit/nuts/leaves that could be harmful
  • Practice good pasture management
  • Be aware of what’s growing in neighbouring areas, or of anything that might be thrown into their paddock, clippings etc

Our horses are like members of our family, and we want to keep them safe, but even the most cared for horse can end up needing veterinary care, because of a whole range of common conditions and this can be overwhelming, both financially and emotionally.

Caring for your horse can be expensive, so a suitable horse insurance policy could help to ensure peace of mind. You can personalise your policy, including adding Vet’s Fees as an Optional Benefit so why not get a free, no-obligation quote today?

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