Gromwell (Purple Gromwell / Pearlwort)
Lithospermum spp. (purpurocaeruleum / officinale)
Horse
Moderate
Get veterinary advice the same day and remove access. Moderate and repeated consumption over several weeks (silent chronic intoxication).
Equio informs, it does not diagnose. When in doubt, call your vet.
What to do now
- Antidote
- No specific antidote. Symptomatic treatment and hormonal support if necessary.
- Time to signs
- Several weeks to several months (chronic toxicity)
- Prognosis
- Excellent for the horse's survival, but poor economic prognosis for a breeder (loss of a foaling year).
- Remove the mare from the infested area.
- Consult an equine veterinarian for hormonal assessment.
- Monitor heat cycles.
Its ID card
- Height
- 30 cm – 1.2 m
- Flowering
- May to July
- Toxic parts
- Entire plant (leaves and seeds).
- Toxin
- Lithospermic acid (anti-gonadotropic) and pyrrolizidine alkaloids (low dose).
- Habitat
- Edges of light woods, hedges, thickets, dry meadows, calcareous soils.
- Soil indicator
- Basic (calcareous), shallow, stony soils, dry edges.
- Regions
- Western and Central Europe, Mediterranean Basin
- In hay
- Yes — stays toxic once dried
- Palatability
- Medium. Occasionally grazed with other edge flora.
When the risk rises
May to July (full bloom and peak attractiveness).
Spotting it in the field
Lungwort, Viper's Bugloss (also blue flowers), Forget-me-not. — smell : odorless or slight herbaceous smell.
- Stems often hairy and erect.
- Elongated leaves.
- Small trumpet-shaped flowers, red turning purplish-blue (G. purpureum) or yellowish-white (G. officinale).
- Extremely hard seeds, resembling small pearls.
Signs to watch for
Chronic (cumulative) toxicity with endocrine disruption.
Dose : Not applicable for chronic toxicity. Repeated ingestion of small quantities over several weeks is problematic.
- Cessation of heat (anestrus) in mares
- Persistent infertility
- Mild lethargy or drop in performance
- Possible very mild long-term liver disorders
- Rarely acute colic (plant is fairly well tolerated digestively)
Who is affected
Other species : Historically known contraceptive effect in humans and sheep.
In pregnant mares : can halt a nascent gestation (embryonic resorption) or block ovulation.
Getting rid of it
Method : Manually pull the plant before seed formation, wearing gloves. Avoid mowing, which can spread seeds. Burn waste.
- Inspect and clear paddocks and field edges before introducing broodmares.
- Avoid overgrazing, which can force horses to consume undesirable plants.
- Identify and eradicate the plant from grazing areas.
Frequently asked questions
Can Equio identify Gromwell (Purple Gromwell / Pearlwort) from a photo?
It can help organize visual clues, but plant identification must remain cautious when horse health is at stake.
Is Gromwell (Purple Gromwell / Pearlwort) 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.