Fool's Parsley
Aethusa cynapium
Horse
Severe
Any suspected ingestion is an immediate veterinary emergency. A few hundred grams of fresh or dried plant.
Equio informs, it does not diagnose. When in doubt, call your vet.
What to do now
- Antidote
- No specific antidote. Symptomatic and supportive treatment (respiration, hydration).
- Time to signs
- 15 minutes to a few hours
- Prognosis
- Very poor if paralysis has set in.
- Absolute veterinary emergency.
- Gastric lavage if possible.
- Administration of activated charcoal.
- Intensive respiratory support treatment.
Its ID card
- Height
- 10 cm – 60 cm
- Flowering
- June to September.
- Toxic parts
- Entire plant.
- Toxin
- Piperidine alkaloids (Coniine, cynapine)
- Habitat
- Gardens, vegetable patches, wastelands, rubble, farmyards, path edges.
- Soil indicator
- Rich, cultivated, manured, loose soils.
- Regions
- Entire Europe
- In hay
- Yes — stays toxic once dried
- Palatability
- Low due to its smell, but very dangerous if hidden in hay or short grass.
When the risk rises
June to September.
Spotting it in the field
Parsley, Wild Chervil, Wild Carrot. — smell : unpleasant garlic or mouse urine smell when crushed.
- Small plant (10 to 60 cm).
- Slender stems, often reddish at the base.
- Highly dissected leaves, shiny underneath (resembling parsley).
- White flowers in small umbels with long, drooping bracts.
- Unpleasant garlic/mouse urine smell when crushed.
Signs to watch for
Acute toxicity.
Dose : A few hundred grams of fresh plant for a 500 kg horse.
- Pupil dilation
- Excessive salivation
- Gait disorders, weakness in hindquarters
- Tremors, muscle spasms
- Respiratory paralysis and death
Who is affected
Other species : Lethal to humans (frequent confusion with parsley), dogs, cattle.
In pregnant mares : teratogenic and lethal risk.
Getting rid of it
Method : Pull the entire plant before flowering, wearing gloves. Destroy uprooted plants (burn or bury deeply).
- Carefully inspect hay and pastures for the presence of this plant.
- Avoid letting horses graze in areas where this plant is known to grow.
- Never feed horses 'weeds' from garden clearing.
Frequently asked questions
Can Equio identify Fool's Parsley from a photo?
It can help organize visual clues, but plant identification must remain cautious when horse health is at stake.
Is Fool's Parsley 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.