Officinal Gratiola, Hedge Hyssop
Gratiola officinalis
Horse
Severe
Any suspected ingestion is an immediate veterinary emergency. A small quantity (a few handfuls of the plant) is enough to trigger severe poisoning.
Equio informs, it does not diagnose. When in doubt, call your vet.
What to do now
- Antidote
- No specific antidote. Intensive supportive care (fluid therapy, symptom management).
- Time to signs
- A few hours to 24 hours.
- Prognosis
- Very poor if kidneys are blocked. Death occurs from uremia or cardiac arrest.
- Immediate veterinary call.
- Massive fluid therapy to support kidneys.
- Manage diarrhea and dehydration.
- Symptomatic treatment for colic.
Its ID card
- Height
- 20 cm – 40 cm
- Flowering
- May to August.
- Toxic parts
- Entire plant (fresh and dried).
- Toxin
- Cucurbitacins (Elatericin) and cardiotonic glycosides (Gratioline).
- Habitat
- Flood meadows, pond edges, peat bogs, mudflats.
- Soil indicator
- Soils flooded in winter, drying out in summer, clayey and acidic.
- Regions
- Central and Southern Europe, France (flood valleys)
- In hay
- Yes — stays toxic once dried
- Palatability
- Very bitter and unpalatable. The main danger is accidental ingestion during wild drinking or if hidden in hay from marshy meadows.
When the risk rises
May to August (flowering).
Spotting it in the field
Skullcap, Water Mint. — smell : slightly acrid when crushed, but the smell is not a reliable indicator of danger.
- Small plant (20-40 cm).
- Hollow stem, often reddish.
- Opposite, elongated, slightly toothed leaves, clasping the stem at the base.
- Solitary tubular flowers, white flushed with pink or pale yellow, arising from leaf axils.
Signs to watch for
Acute toxicity.
Dose : A few hundred grams of fresh or dried plant for a horse.
- Fulminant colic
- Profuse hemorrhagic (bloody) diarrhea
- Complete halt of urine production (anuria, kidney failure)
- Severe visual disturbances
- Convulsions and collapse
Who is affected
Other species : Highly toxic to cattle and horses (which are the most sensitive). Fatal to humans.
In pregnant mares : extremely violent abortifacient.
Getting rid of it
Method : Pull the plant wearing gloves before flowering. Destroy by burning or bury deeply. Prevent spread.
- Identify and fence off wet areas where this plant grows.
- Do not harvest hay from potentially contaminated meadows.
- Closely monitor horses grazing near wetlands.
- Educate owners about the risks of this plant.
Frequently asked questions
Can Equio identify Officinal Gratiola, Hedge Hyssop from a photo?
It can help organize visual clues, but plant identification must remain cautious when horse health is at stake.
Is Officinal Gratiola, Hedge Hyssop 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.