First Walk is on Us!

✓ GPS tracked walks
✓ Activity reports
✓ On-demand walkers
Book FREE Walk

Jump to Section

What is Hellebore Poisoning?

Like most species of livestock, equines do not choose to ingest unpalatable weeds or plants unless quality food is in short supply. The presence of nutritious feed, fresh legumes and copious amounts of green grass keep livestock well-nourished and content, and away from the danger of ingesting highly toxic vegetation. However, in instances of overgrazing, drought, and other times when safe and preferable food is lacking, hungry horses will go in search of whatever vegetation is readily available. Other than trying to thwart starvation, horses may also unknowingly consume toxic  plants by eating the leaves, stems and flowers that sometimes contaminate otherwise quality hay.

Grass clippings that blow from one pasture to the next is yet another example of how toxic weeds and plants invade pastures. One plant that is highly poisonous to horses is the hellebore (often called Christmas rose), which grows freely across the fields and pastures of the United States. Each part of the plant, including the roots, stems and flowers, are similarly poisonous. Like most poisonous plants, when consumed in small amounts, the hellebore plant may cause symptoms of gastrointestinal upset such as diarrhea and mild abdominal discomfort. In instances of greater consumption, the toxic properties of the plant may inflict irreversible damage to the equine’s major organs, particularly the heart and kidneys. Left untreated, such a significant level of toxicity can cause death. 

While horses and cattle appear to be most vulnerable, hellebore growing in the household places domestic pets at risk. With its festive beauty and Christmastime blossoming, the plant is as beautiful as its name. As a part of many holiday displays, it is readily available for curious dogs. Thankfully, instances of life-ending poisoning are few as most dogs will forego a poisonous plant for a delicious, dependable meal. What makes the hellebore (also called Christmas rose, lenten rose and Easter Rose) so dangerous are the type of toxins found within all parts of the plant, including the glycosides hellebrin, helleborin, and helleborein, among others. Such cardiac glycosides, known as cardenolides, lead to threatening heart palpitations and contractions.

For older horses, this type of cardiac insult may be insurmountable. The glycosides place significant stress on the heart and kidneys, and cause a pronounced heartbeat and possible kidney failure. Left untreated, a horse consuming large amounts of hellebore is at risk of muscle spasms, convulsions, confusion and death. If you suspect that your horse has been poisoned, contact your veterinarian immediately. Fast treatment is essential in order to keep your horse healthy.

In instances of substantial consumption, the toxic properties of hellebore may cause irreversible damage to the equine’s major organs, particularly the heart and kidneys.

Book First Walk Free!

Symptoms of Hellebore Poisoning in Horses

Symptoms of poisoning by the hellebore plant include:

  • Diarrhea
  • Respiratory distress
  • Labored breathing
  • Drooling
  • Swollen, painful abdomen
  • Unquenchable thirst 
  • Lethargy

Causes of Hellebore Poisoning in Horses

In cases of significant hellebore ingestion, the toxic properties of the hellebore plant lead to cardiac distress, renal failure or death. Cardiac glycosides cause heart palpitations and contractions. The glycosides also place significant stress on the kidneys, and may cause renal failure.

Diagnosis of Hellebore Poisoning in Horses

Potential plant poisoning in horses calls for immediate veterinary care. Diagnosis will call for a detailed report of symptoms. If you can obtain a sample of questionable vegetation, show the vet for identification. He may choose at one point to walk the pasture and paddock to view the area where the offending plant is located; the grazing pattern or evidence of disturbed plants may indicate an approximate amount ingested.

When it comes to toxicity, making a definitive diagnosis can be challenging because gastrointestinal symptoms can indicate many types of illness. Part of the diagnostic process calls for blood work and in cases of possible renal damage, a urine sample will be collected. Additionally, plant material may be found in the mouth of your horse; furthermore, the manure may contain plant particles. An echocardiogram will reveal any irregularities to the heart and its contractions.

Treatment of Hellebore Poisoning in Horses

The course of treatment for hellebore toxicity depends upon the amount of the plant ingested, as well as the lapse of time between the poisoning and veterinary treatment. As with humans, each horse will respond differently to the presence of a toxin. Variables such as the age and overall health may play a significant role in the severity of symptoms, the potential response to treatment, as well as the likelihood of a full recovery. 

Since H. niger contains cardiac glycosides, known as cardenolides, the potential for damage to the heart and kidneys is significant. For older horses, this type of cardiac insult may be insurmountable. The glycosides place significant stress on the heart by increasing contractions and a pronounced heartbeat. Left untreated, a horse consuming large amounts of hellebore is at risk of muscle spasms, convulsions, confusion and even death. 

Due to the availability of treatment, however, many horses can recover from the ingestion of poisonous plants such as hellebore. The vet may give a cathartic medication in hope of clearing any remaining toxins. IV fluids may help to support the kidneys and also replace loss of fluids due to dehydration. Activated charcoal is likely given, as well as nausea medication. Other treatments will depend on the level of toxicity.

Recovery of Hellebore Poisoning in Horses

With all poisonous, expeditious treatment is necessary. The time lapse between the initial insult and veterinary care will influence the horse’s prognosis. 

After acute symptoms are treated, it’s recommended that you focus on prevention. Become aware of all plants in the pasture, and search daily for any opportunistic weeds, or grass clippings. Your vet can educate you on poisonous plants in your area. Also, get your hay from one trusted supplier in order to lessen chances of contamination.