Common Comfrey
Symphytum officinale
Horse
Moderate
Any suspected ingestion is an immediate veterinary emergency. Chronic intoxication: regular consumption over several weeks or months.
Equio informs, it does not diagnose. When in doubt, call your vet.
What to do now
- Antidote
- No specific antidote. Intensive veterinary liver support treatment.
- Time to signs
- Several weeks to several months for chronic symptoms.
- Prognosis
- Grave if liver damage is already advanced. The liver damage caused by pyrrolizidine alkaloids is cumulative and irreversible.
- Stop ingestion.
- Blood sample to assess liver enzymes.
- Veterinary liver support (milk thistle, vitamins).
Its ID card
- Height
- 0.3 m – 1.5 m
- Flowering
- May to August
- Toxic parts
- Entire plant (roots, leaves). Remains toxic in hay.
- Toxin
- Pyrrolizidine alkaloids (Lycopsamine, symphytine)
- Habitat
- Ditches, riverbanks, damp meadows, gardens (cultivated), woodland edges.
- Soil indicator
- Heavy, deep soils, rich in nitrogen, and very moist.
- Regions
- Entire Europe
- In hay
- Yes — stays toxic once dried
- Palatability
- Low (leaves are very rough and hairy), but may be grazed if grass is scarce or hidden in hay.
When the risk rises
All year (hay); May to August (fresh growth).
Spotting it in the field
Foxglove (before flowering), Borage. — smell : slight, slightly acrid smell when crushed, but not very pronounced.
- Large herbaceous plant (up to 1m).
- Very rough and prickly to the touch.
- Large, thick, oval, and pointed leaves that extend down the stem ('decurrent').
- Hanging tubular bell-shaped flowers, often purplish, pink, or yellowish-white.
Signs to watch for
Predominantly chronic (cumulative) toxicity.
Dose : The exact lethal dose is difficult to determine due to cumulative toxicity, but regular long-term consumption is dangerous.
- Chronic weight loss and apathy
- Jaundice (yellow mucous membranes, sign of liver failure)
- Chronic digestive disorders
- Photosensitization (abnormal sunburns)
- Late neurological symptoms (hepatic encephalopathy)
Who is affected
Other species : Hepatotoxic for humans (prohibited for internal use in many countries) and pigs/cattle.
In pregnant mares : toxins cross the placental barrier and enter milk, damaging the foal's liver.
Getting rid of it
Method : Uproot the entire plant, including roots, before flowering. Wear gloves to avoid contact with irritating sap. Destroy the uprooted plant to prevent dissemination.
- Inspect pastures and remove comfrey before horses have access.
- Avoid mowing comfrey and feeding it as hay or silage.
- Be wary of old popular beliefs regarding comfrey use for animals.
Frequently asked questions
Can Equio identify Common Comfrey from a photo?
It can help organize visual clues, but plant identification must remain cautious when horse health is at stake.
Is Common Comfrey 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.