Lily of the Valley
Convallaria majalis
Horse
Critical
Any suspected ingestion is an immediate veterinary emergency. Only a few stems (or bulbs) can be fatal. Even the vase water that contained the flowers is highly toxic.
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 (anti-arrhythmics, diuretics, fluid therapy).
- Time to signs
- 15 minutes to a few hours
- Prognosis
- Grave if intervention is not extremely rapid.
- Call veterinarian immediately.
- Do not allow the horse to walk (risk of cardiac arrest with exertion).
- The veterinarian will administer anti-arrhythmics (atropine) and activated charcoal if ingestion was very recent.
Its ID card
- Height
- 0.2 m – 0.4 m
- Flowering
- April to June
- Toxic parts
- Entire plant (flowers, leaves, bulbs/rhizomes, and especially the small red berries that appear in late summer).
- Toxin
- Cardiotonic glycosides (Convallatoxin, convallamarine)
- Habitat
- Open woodlands, shaded edges, gardens, ornamental beds.
- Soil indicator
- Forest soils, light, fresh, humus-rich, often calcareous.
- Regions
- Entire Europe, North America
- In hay
- Yes — stays toxic once dried
- Palatability
- Low to medium. The risk comes from discarded garden waste, or horses foraging in undergrowth in early spring.
When the risk rises
April-May (leaves/flowers) and August-September (red berries).
Spotting it in the field
Wild garlic (before flowering, but lily of the valley has absolutely no garlic smell when leaves are crushed), Autumn Crocus. — smell : very strong and pleasant smell from the flowers, but leaves and stems are odorless or have a slightly herbaceous scent.
- Two large, smooth, oval, pointed leaves of a beautiful tender green.
- Flowering stem bearing small, very fragrant white bells (May).
- In autumn, the flowers give way to small, bright red berries.
Signs to watch for
Acute toxicity.
Dose : A few grams of fresh or dried plant can be sufficient for a horse, depending on the part ingested and toxin concentration.
- Severe cardiac disorders (arrhythmia, extreme slowing of pulse)
- Violent colic, vomiting (gagging efforts)
- Often bloody diarrhea
- Muscle tremors and general weakness
- Cardiac arrest (syncope) and death
Who is affected
Other species : Fatal to absolutely all companion mammals (dogs, cats, rabbits) and humans (especially children ingesting berries or vase water).
In pregnant mares : fatal to the mare (and therefore the fetus).
Getting rid of it
Method : Uproot the entire plant, including rhizomes, wearing gloves. Destroy waste by incineration to prevent dissemination.
- Never plant lily of the valley near paddocks or grazing areas.
- Regularly inspect areas accessible to horses to remove any lily of the valley plants.
- Educate owners about the dangers of lily of the valley, including vase water.
Frequently asked questions
Can Equio identify Lily of the Valley from a photo?
It can help organize visual clues, but plant identification must remain cautious when horse health is at stake.
Is Lily of the Valley 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.