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Along the paths in the forest, on the roadside or in the paddock grows a lot of things that interest a horse. Especially during a short break, horses often take the opportunity to nibble on plants along the way. A small inattention of the rider is enough for a horse to pluck such plants. Sometimes this happens unnoticed.

It becomes dangerous if it is a poisonous plant. It is certainly an advantage for every rider to acquire basic botanical knowledge. This would help identify poisonous plants and prevent the horse from eating them. Especially alkaloids (organic compounds containing nitrogen) affect the animal and human organism.

Here is a list of plants that are toxic to a horse:

You would like to know not only if your horse was poisoned, but also with what? A detailed analysis will bring both to light. Help your horse today and order a hair analysis. 

Boxwood (Buxus sempervirens)

This evergreen plant is one of the most popular trees and are often planted for hedges and in gardens / front yards. Boxwood can cause serious poisoning because it contains a whole range of alkaloids. These initially have a stimulating effect when consumed. However, as a consequence, paralysis and lowering of blood pressure occur. Likewise, nausea, drowsiness, delirium and convulsions may occur. At the same time, boxwood is said to have a healing effect. The lower the body weight, the faster the lethal dose is reached in humans and animals.


This is a shrub with abundant yellow flowers. The term common laburnum (Laburnum anagyroides) is also often used. This plant enchants in the spring with bright yellow flowers, but nevertheless, the laburnum is poisonous. The cystine contained in the plant shortly after ingestion causes symptoms such as burning throat, thirst, trembling, nausea stomach pain to hallucinations, convulsions and paralysis.

Hollowroot / birthwort

This herb was used in earlier times for wolf hunting. This is an ancient medicinal plant, which, however, is very poisonous (Aristolochia clematitis). The plant is conspicuous by small yellow flowers with large roundish leaves. Its main flowering period is in May and June.


The yew (Taxus baccata) is extraordinarily versatile. It can be used as a free-growing tree for solitary planting, as well as for hedges and any type of topiary. The appearance ranges from coniferous shrub to a small tree. However, the needles are highly poisonous. Even a handful presents a lethal dose for horses.


First of all, it is worth mentioning the different varieties, namely large-flowered, yellow or red. Generally, these are large, downward sloping calyx flowers on perennials, which are often found in the forest. The flowering period is mainly in midsummer. Its magnificent appearance can really attract horses. Because of its strong toxicity, it is not recommended to plant these plants in the garden. The parts of the plant have a strong bitter taste, in this respect, serious poisoning rarely occurs.

Robinia (Robinia pseudacacia)

This plant is a beautiful tree with whimsical growth. Not for nothing here we talk about a false acacia (Robinia pseudoacacia). Especially globe robinia decorates sunny places with its feathery foliage. The flowering period is from May to June. This plant is classified as highly poisonous.

Aconitum / wolfsbane / monkshood

For a long time, aconitum has had a permanent place in cottage gardens. Depending on the species, this plant presents its pretty flowers between early summer and autumn. In the past, the poison of aconite was used to prepare arrowheads. After intense skin contact with the plant’s sap, symptoms such as temporary numbness and nausea are possible. Even though aconite is beautiful, it should not be planted in places accessible to children and animals.

Autumn crocus

A deadly poison from nature. Whether human or animal, consumption of this plant is deadly. Because of its toxicity, this plant does not like to be seen in pastures. Spring is the best time to control this plant. In 2010, autumn crocus (Colchicum autumnale) was chosen as the poisonous plant of the year.

Pheasant’s eye / adonis

This perennial, with round, yellow, serrated flowers blooms from February to April. It is classified as hardy and poisonous. The adonis plant (Adonis amurensis, Adonis davurica) originates from Japan, China, Korea and Eastern Siberia. In the wild, this plant is now very rare and therefore also subject to nature conservation.

Ragwort /toadflax

A typical meadow plant with round yellow flowers. Special caution is required here. Especially in North Rhine-Westphalia this poisonous plant has spread. Even the Chamber of Agriculture in North Rhine-Westphalia recommends some measures to control the spread. The danger of ragwort (Jacobaea vulgaris) is not to be underestimated, even chronic diseases can be the consequence in case of poisoning. Horses, in particular, react especially sensitively.


The flowering period is from May to October. The small-sized yellow flowers have only four petals. Celandine (Chelidonium majus) is used in modern medicine against cramps in the gastrointestinal tract. However, caution is advised because liver damage can result. For animals, fresh celandine is very toxic. Typical symptoms include drowsiness, convulsions, bradycardia, hypertension, cardiac arrhythmias, and shock. Due to the unpleasant taste of the plant, poisonings are rather rare.


Few hedge plants are as robust and adaptable as the privet (Ligustrum). Especially in winter, this plant stays green longer and is therefore popular as an ornamental plant in the garden. The flowers appear in June. The bark of the shoots is strikingly light gray. This plant, with small yellowish-white flowers spreads an intense fragrance. The fruits (black berries) are gladly eaten by birds. Both the leaves and the berries contain a poisonous substance, which causes vomiting, diarrhea and abdominal pain. Already 100 g of this substance is said to be fatal for horses.

Water hemlock

This is a marsh meadow plant with branched group shrubs and white flowers. Eating the tubers, which are highly poisonous, causes respiratory paralysis, resulting in death. The yellowish sap of the plant turns orange-yellow when exposed to air, which progressively turns brown. Its odor is celery-like. Especially the root contains the highly toxic cicutoxin. The poison is effective even in the smallest doses (2 – 3 g).

Lily of the valley

With its snow-white and fragrant flowers, the lily of the valley (Concallaria majalis) welcomes spring. It has distinctive long leaves that grow vertically upwards, almost stemless. Although this plant is highly poisonous, it finds its place in medicine. After consulting a doctor, the preparations from the dried, above-ground parts of the plant can be taken for diseases of the heart. Regarding toxicity, care should be taken that neither children nor animals drink the flower water, because after some time the toxic ingredients of the plant pass into the water.


This shrub-sized nightshade plant is probably one of the best-known poisonous plants. Belladonna (Atropa belladonna) is notable for its mostly black, cherry fruit-like berry fruits. It was voted poisonous plant of the year in 2020. The alkaloid atropine is predominant in the fruit, whereas hyoscyamine is predominant in the leaves. Ingestion causes, depending on the dose, general agitation and physical restlessness, but also severe confusion, convulsions and fits of raving madness. As a result, paralysis often occurs. Death occurs due to respiratory paralysis.

Black henbane / witchweed

Henbane (Hyposcyamus niger, Solanaceae) is a poisonous plant and, like other members of the nightshade family, contains potent tropane alkaloids. The effects extend to the nervous system, certain involuntary functions are abolished. The toxicity is classified as very high. Despite its toxicity, this plant has long been used as a medicinal plant in ancient medicine. Even today, its antispasmodic and sedative effects are still prominent. In case of overdose, severe poisoning is the result.