Image of Ragwort, a common plant toxic to horses

Which plants are most toxic to horses? In this series of posts, I describe the most common plants that are toxic to horses.


Ragwort (Senecio jacobaea) is a biennial plant, abundant in Britain. It can grow from 30cm to a meter in height. Ragwort has bright yellow flowers, and the rough lobed leaves which give it its name. This plant was classed as injurious under the Weeds Act, 1959. Landowners may be subject to prosecution if they leave Ragwort on their land.

What the herbalist says:

The herbalist Culpeper tells us that: The greater common Ragwort hath many large and long dark green Leavs lying on the ground, very much rent and torn on the sides into many pieces, from among which rise up somtimes but one, and sometimes two or three square or crested blackish or brownish Stalks three or four foot high, sometimes branched bearing diverse such like Leavs upon them at several distances unto the tops, where it brancheth forth into many Stalks bearing yellow Flowers, consisting of diverse Leaves set as a Pale or Border, with a dark yellow thrum in the middle, which do abide a great while, but at last are turned into Down, and with the smal blackish gray Seed are carried away with the wind. The Root is made of many Fibres, whereby it is firmly fastned into to the ground, and abideth many yeers.

The active agent:

Poisonous agents in Ragwort are of the pyrrolizidine alkaloid family. The most toxic of these are known as cyclic diesters. Symptoms of poisoning may not appear immediately. Animals may have to graze the plants for some time before intoxication. The effects are various such as diarrhoea and effects on the nervous system, which range from restlessness to paralysis. In the equestrian world, such intoxication is known as “sleepy staggers“.

Herbal Medicine

In herbal medicine, Ragwort has several uses. Traditionally it is used for the relief of gout and sciatica, and as a gargle for sore throats.

Clearing Ragwort from the paddock:

The dried Ragwort plant retains its toxicity. When I clear Ragwort from paddocks, I take certain precautions. We use a heavy-duty waste disposal sack so that plants do not touch the wheelbarrow or any other equipment. Gloves are essential to avoid self-contamination. I immediately place the plants in an incinerator for destruction by fire. It is important to leave no trace by the incinerator should animals have access. One must dig the roots out. Ragworts seem to be able to regenerate from even the tiniest rootball, so the more rigorous one is, the better.


Other articles about plants appear on my Professional Facebook Page.
If there is a plant you would like me to write about, please get in touch via Contacts.

Quarterly Holistic Newsletter

If you have enjoyed this article, please keep in touch and sign up for our Quarterly Holistic Newsletter.

Cover image of Quarterly Newsletter

Keith Allison: A guide to Plants Poisonous to Horses. J.A. Allen. Revised edition, 2011.
John Gerarde: The Herball or General Historie of Plantes, 1636.
Culpeper: Index Of Herbs By Nich. Culpeper, Gent. Student in Physick and Astrologie, 1616, 1654

Please follow and like us: