Water Hemlock
Cicuta virosa
Horse
Critical
Any suspected ingestion is an immediate veterinary emergency. 200 to 300 grams of root (sometimes less) are lethal.
Equio informs, it does not diagnose. When in doubt, call your vet.
What to do now
- Antidote
- No specific antidote. Intensive symptomatic treatment: anticonvulsants (benzodiazepines, barbiturates), respiratory and cardiovascular support. Success depends on the speed of intervention.
- Time to signs
- 15 to 60 minutes
- Prognosis
- Grave. Death often occurs before the veterinarian can arrive.
- Call a veterinarian immediately.
- Do not induce vomiting.
- Keep the horse calm and warm.
- Closely monitor for neurological signs.
Its ID card
- Height
- 0.5 m – 1.5 m
- Flowering
- June to September
- Toxic parts
- The entire plant is toxic, but the root (rhizome) is the most lethal part.
- Toxin
- Unsaturated alcohols (Cicutoxin)
- Habitat
- Riverbanks, ponds, marshes, flooded ditches.
- Soil indicator
- Water-saturated soils, peat bogs, mud.
- Regions
- Northern Europe, Central Europe, Marshy areas
- In hay
- Yes — stays toxic once dried
- Palatability
- The sweetish root is sometimes dug up and accidentally eaten when the horse drinks or grazes on the banks.
When the risk rises
Spring (when roots are easily pulled from muddy soil) and summer.
Spotting it in the field
Wild celery, Angelica, other Apiaceae (umbellifers). — smell : strong, acrid odor, reminiscent of parsley or celery, especially when crushed or cut.
- Aquatic or semi-aquatic plant.
- Hollow, smooth, and hairless stem.
- White flowers arranged in compound umbels.
- Thick, segmented rhizome that secretes a yellowish sap with a characteristic parsley/celery odor.
Signs to watch for
Acute toxicity
Dose : Approximately 200-300g of root for an adult horse.
- Extremely violent convulsions
- Hypersalivation (foaming at the mouth)
- Dilation of the pupils
- Severe teeth grinding
- Death by respiratory arrest within hours
Who is affected
Other species : Lethal to all mammals, including humans.
In pregnant mares : death of the mother.
Getting rid of it
Method : Uproot the entire plant, including the roots, wearing impermeable protective gloves. Destroy the plant by incineration or deep burial to prevent spread.
- Identify and remove the plant from pastures and water sources.
- Closely monitor horses when grazing near wet areas.
- Provide a clean and safe water source to prevent horses from drinking from potentially contaminated water.
Frequently asked questions
Can Equio identify Water Hemlock from a photo?
It can help organize visual clues, but plant identification must remain cautious when horse health is at stake.
Is Water Hemlock 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.