Monkshood
Aconitum napellus
Horse
Critical
Any suspected ingestion is an immediate veterinary emergency. Less than 300 grams of leaves are lethal for an adult horse.
Equio informs, it does not diagnose. When in doubt, call your vet.
What to do now
- Antidote
- No specific antidote. Intensive symptomatic and supportive treatment (cardiovascular, respiratory).
- Time to signs
- A few minutes to 1 hour
- Prognosis
- Grave. Death can occur within 1 to 6 hours.
- Immediate veterinary call.
- Support vital functions (cardiorespiratory).
- Close monitoring of vital signs.
- Prevent absorption (if possible and safe).
Its ID card
- Height
- 0.5 m – 1.5 m
- Flowering
- June to September
- Toxic parts
- Entire plant (roots, leaves, flowers).
- Toxin
- Diterpenoid alkaloids (Aconitine)
- Habitat
- Mountains (Alps, Pyrenees), edges of damp woods, often cultivated in gardens.
- Soil indicator
- Rich, deep, moist, and shaded soils.
- Regions
- Europe (Mountains), Temperate zones
- In hay
- Yes — stays toxic once dried
- Palatability
- Avoided when growing, but poisonings are possible via contaminated mountain fodder or garden waste.
When the risk rises
June to September.
Spotting it in the field
Larkspur (Delphinium), which is also toxic. — smell : odorless
- Majestic and tall plant.
- Intense blue-violet helmet-shaped flowers ('Jupiter's Helmet').
- Dark green, deeply cut leaves.
- Erect stem.
Signs to watch for
Acute toxicity
Dose : Less than 300 g of fresh leaves for an adult horse.
- Hypersalivation and colic
- Agitation followed by extreme weakness
- Heart rhythm disorders (fibrillation)
- Pharyngeal paralysis (inability to swallow)
- Asphyxiation and cardiac arrest
Who is affected
Other species : Lethal to all animals and humans. Even prolonged skin contact with the sap is dangerous.
In pregnant mares : lethal for both the mare and the foal.
Getting rid of it
Method : Uproot the entire plant, including roots, before flowering. Wear gloves and protective clothing. Destroy the plant by incineration.
- Identify and remove Aconitum napellus from pastures and stable surroundings.
- Never use hay from areas where this plant is present.
- Wear gloves when handling the plant to avoid skin contact.
- Educate staff and owners about the dangers of this plant.
Frequently asked questions
Can Equio identify Monkshood from a photo?
It can help organize visual clues, but plant identification must remain cautious when horse health is at stake.
Is Monkshood dangerous in hay?
This entry flags hay vigilance. Isolate suspicious forage and ask for professional advice if exposure is possible.
This page is informational. If ingestion is likely, if signs appear, or if the horse is fragile, contact a veterinarian immediately.