It is that time of year again where many of us will be tirelessly digging out ragwort from our fields. But why do we need to do it?

Why is Ragwort poisonous?

Ragwort contains toxins called pyrrolizidine alkaloids which if ingested in sufficient quantities can cause poisoning in horses. Small amounts of ragwort eaten over a long period of time causes accumulation of the toxin in the liver which results in liver damage. Alternatively large amounts ingested in a short period of time will also cause liver damage. Although the mature plant is generally avoided by horses due to its bitter taste, the nature of this cumulative effect means even small amounts of ragwort in your horses field should be removed.

What are the symptoms of Ragwort poisoning?

The toxin causes liver damage therefore symptoms are consistent with liver disease or failure.  It is important to remember that horses may not display symptoms until the condition is advanced.

Symptoms include:


Photosensitivity – inflammation of white-haired/pink-skinned areas when exposed to sunlight

Weight loss



Neurological signs – blindness, compulsive walking, head pressing

For those not displaying symptoms,  we can assess liver damage through a simple blood test. This blood test can detect elevated liver enzymes however does not confirm a diagnosis of ragwort poisoning; a liver biopsy can tell us more information about cause of elevated liver enzymes.

Treatment of Ragwort poisoning

Treatment is based primarily on supportive care to aid liver regeneration. In severe cases, liver damage can be irreparable and prognosis is guarded even with treatment.

Supportive therapies may include milk thistle, vitamin E and selenium.

Prevention and control

It is not enough to assume your horse will choose not to eat ragwort so control is essential. Regular checks of your horses field will identify presence of any new plants so it is important to know what we are looking for throughout the year.

Seedlings can start to appear in autumn – they are about 1-1.5cm tall

Rosettes are generally seen from early spring onwards

Mature plants flower between May and October – these can reach up to 2m!

Ragwort removal

  • DO wear gloves (can be harmful to humans too)!
  • DO remove plants before flowering, at their rosette stage if possible and whilst ground is soft
  • DO remove as much root as possible as it will regenerate from any root left behind – purpose designed forks will help with this
  • DON’T dispose of pulled ragwort on muck heaps as this will encourage plants to re-seed (DEFRA can advise on appropriate methods of disposal)

Spraying is an option for large affected areas however the dead plant is still poisonous so all traces need removing before anything is to graze on the area again.

Ragwort can be disguised into hay and is more palatable this way so may be accidentally ingested – look for thick fibrous stems, yellow flower heads, leaves with ragged edges and remove where possible.

If you have any concerns or would like some advice on Ragwort please remember to speak to your vet - we can be contacted on 07747 717474, please note we can only give opinions on horses in our area who are registered clients. Enjoy the sun! Holly x