The Danger of Ragwort Poisoning for Horses - 
A Slow and Painful Death

Ragwort should be cleared from fields grazed by horsesRagwort poisoning is one of the most common causes of plant poisoning in equines; with young horses and ponies most at risk.

It destroys the horse's liver, leading to a slow and painful death. Most horses affected by ragwort poisoning die after suffering for periods varying from a week to several months.

Unfortunately once symptoms of ragwort poisoning have appeared in a horse or pony very little can be done to save it and, sadly, it will usually die.

A horse or pony can be poisoned by ragwort without even having any plants in their grazing area. Seeds from ragwort plants in neighbouring paddocks and fields can be blown across and contaminate an area apparently free from ragwort. A horse or pony can inhale or eat these seeds and become affected by cumulative poisoning.

Although Ragwort flowers are only seen during the from May to October, the effects of poisoning can occur at any time of the year. The plant is most poisonous during its first year of growth when it appears as a dense rosette of leaves , but with no flowers.

The poisonous effect of ragwort on a horse is cumulative - a small amount of the plant eaten over a long time is just as dangerous as a lot being eaten in just a few days.

Symptoms of poisoning do not always appear immediatley after a horse or pony has eaten a large amount of ragwort. It may take as long as 4 weeks to 6 months for the equine liver disease to develop.

Different horses have different reactions to to the toxins in the plant.

Poorly managed grazing for horses is particularly likely to suffer ragwort infestations. Closely growing grass restricts the growth of ragwort, whilst overgrazed paddocks leave patches of soil that leave perfect conditions for ragwort seeds to germinate.

Horses that eat ragwort as 5% or more of their total daily diet for more than 20 consecutive days can be expected to die within 6 months.

It is believed that some equines get to like the bitter taste of ragwort and may choose to eat it even when there is good grazing available.

Hay is a common source of ragwort poisoning. Unfortunately when ragwort is dried it loses its bitter taste and horses are no longer able to detect it. So any hay, haylage or even chaff which contains the weed will be readily eaten. It is really important to check bales of hay for ragwort as the toxins are not destroyed whent he plant dies - but it may not always be easy to recognise ragwort when it is dried and fragmented.

Why you buy hay it may be possible to check the source, ask what method of weed control was used and maybe even visit the hayfield that the hay was cut from.

There are 2 acts of goverment in the UK concerning the control of ragwort.

When ragwort appears on agricultural or equestrian property the landowner is legally required to treat and clear it. DEFRA may take action where this is not done.


  • Cutting ragwort down will not kill the plant - it may even encourage more growth! However, as a interim measure, cutting may prevent the production and spreading of seed.

  • Chemical spraying with a systemic weed killer can be effective when used on the the early rosette stage of ragwort growth; but is not so effective on older stemmed plants.

  • Spring is the best time for spraying fields for grazing, but don't spray in springtime if you intend cutting hay from the treated fields.

  • Spraying of fields intended for hay production should be carried out in the
    previous autumn.

  • Affected fields should all be sprayed at the same time so as to avoid ragwort seeds spreading and germinating in
    the bare areas left when the dead weeds are removed.

  • When ragwort has died down after being sprayed it must be removed and carefully destroyed before the fields can be used again for grazing animals.

  • Ploughing can be an effective method of controlling ragwort as long as the grass
    reseeding results in a thick, healthy covering of grass. This can be encouraged by the use of fertiliser.

  • Pulling or digging up ragwort plants -
    a basic control method that is appropriate when there is not too much ragwort to deal with. You should wear rubber gloves to pull up ragwort, as the plants are also poisonous to humans and the toxins can enter the bloodstream through the skin.

  • Bits of root will be left in the ground after digging or pulling up - new growth will have to be removed each year.

  • All pulled plant material should be properly disposed of (see opposite).

  • Good grazing management is essential to the long term prevention of Ragwort infestation. Do not overgraze or overstock fields. Keep fertilized and do not allow to become poached or muddy.


Ragwort is known as an "injurious weed" and its control is governed by the 1959 Control of Weeds Act across the whole of the UK.

When the 2003 Ragwort Control Act, which only applies to England & Wales, came into effect in February 2004 amending the earlier Weeds Act, it gave more protection to animals, including horses, from the serious effects of Ragwort poisoning

The combination of the 2 laws makes it easier for government authorities to serve notices to landowners and/or occupiers to treat and clear land infested with ragwort. They may prosecute those that do not comply with these notices.

A Code of Practice is available which gives advice and guidance on all matters on dealing with Ragwort.


  • Ragwort has bright yellow flowers appearing from May to October.
  • It is naturally a biennial plant - its takes two years to mature to flowering.
  • Ragwort can act as a perennial plant
    if it is cut or mown.
  • In its first year of growth ragwort
    has a dense rosette of leaves growing close to the earth
  • In their second year ragwort grows to
    between 30 and 100cm high.
  • Mature plants have dark green leaves with ragged, irregular edges and woody stems
  • It is most poisonous in its first year
  • Each ragwort plant can produce about 150,000 seeds
  • The seeds have a 70% germination rate.
  • Seeds can remain dormant for up to 20 years.
  • Seeds are spread widely by the wind.


  • The clinical signs of equine ragwort poisoning usually only become apparent when liver failure has already occurred.
  • Unusual behaviour,restlessness and uncoordinated movement due to the harmful effects of the toxins on the horse's brain.
  • Depression
  • Loss of condition
  • Weight loss
  • Dull coat
  • Poor appetite
  • Constipation
  • Photosensitisation - with inflammation of the unpigmented areas of the skin (not the same as sunburn).
  • Jaundice
  • Diarrhoea
  • Seizures
  • Blindness
  • Coma
Diagnosis can be helped by analysing blood samples or performing a liver biopsy to look for any signs of liver damage in the horse
ragwort - poisonous to horses

Treating Ragwort Poisoning

The first and most obvious thing to do is to remove all traces of ragwort from the horse's diet and environment.

However once signs of ragwort poisoning become evident it is often too late for any successful treatment, although some horses do survive.

There is no effective treatment for Liver failure ( as a result of ragwort poisoning) - the liver can only be helped to repair itself.

Feed the horse a healthy diet with easily digestible proteins and a high carbohydrate level which does not place to much demand on the liver.

Consult your veterinary surgeon who will discuss the latest available treatments.

ragwort a poisonous weed

Diposal of Ragwort Plants

  • Defra will provide guidance on the disposal of ragwort - contact them for more detailed information.
  • Ragwort plants should only be moved in sealed bags or containers as seeds may fall and be dispersed in transit.
  • Freshly uprooted ragwort will not burn well due to its moisture content. and
  • Attempting to burn fresh ragwort will result in dark smoke.
  • If you are going to burn ragwort let it dry out first in a covered pile or in paper sacks.
  • Do not carry out disposal near ditches, watercourses.
  • Ragwort can only be composted using a fully contained composting system where the draining liquid is contained, and where the process isn't affected by the weather. The process must meet The British Standards PAS 100;2005 specification for composted materials available from WRAP.
  • For horse owners rotting down ragwort is likely to be a more practical solution than composting - use a standard compost bin with a lid to and add small quantities of ragwort mixed with grass cuttings some water may be needed to keep the mixture moist. A period of 12 months should be left before the compost bin is emptied.
  • Ragwort is poisonous to humans. It can enter the bloodstream through the skin: Wear protective clothing when handling.
ragwort a poisonous weed

Ragwort poisoning - one of the most common causes of plant poisoning in equines,
destroying the liver. Young horses and ponies most at risk. For prevention grazing
should be treated with weedkiller to destroy ragwort