Iris Poisoning in Horses

Iris Poisoning in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost
Iris Poisoning in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost

What is Iris Poisoning?

The Iris is also known as Bearded Iris or Flag, but they are all basically the same. These attractive perennials grow up to three feet tall, with long sword-shaped leaves and large showy flowers that can be any color. This poisonous beauty can be found near marshes, by lakes, and near riverbanks. Because of their toxicity, it is essential that you prevent your horse from having access to the Iris. Although many experts say it is just the root that causes the poisoning, but there has been no proof that the rest of the plant is healthy or safe in any quantity if ingested by your horse.

The Iris (Iridaceae) has many varieties, types, and subtypes, and they are just as toxic as they are beautiful. The root contains iridin, undecylenic acid, tridecylenic acid, myristic acid, ascorbic acid, and terpenes which are all poisonous substances that can make your horse quite ill. In fact, the larger plant that is commonly found growing as a weed in fields, the Iris versicolor, has very high amounts of the toxin iridin, which can produce gastrointestinal symptoms such as diarrhea, nausea, and skin and mucous membrane irritation.

Symptoms of Iris Poisoning in Horses

Symptoms depend on the amount and part of the plant your horse consumed. However, the most common include:

  • Breathing difficulty
  • Diarrhea
  • Nausea
  • Abdominal pain


There are over one thousand species, types, and subtypes of Iris, but the most common ones indicated in equine poisonings are:

  • Iris versicolor
  • Iris kemaonensis
  • Iris germanica
  • Iris florentina
  • Iris flavescens
  • Iris atropurpurea
  • Iris albicans


Causes of Iris Poisoning in Horses

  • Iridin
  • Undecylenic acid
  • Tridecylenic acid
  • Myristic acid
  • Ascorbic acid
  • Terpenes


Diagnosis of Iris Poisoning in Horses

If you believe your horse has ingested Iris plants or if you have already seen symptoms of this disorder, then you need to call your veterinarian as soon as possible. If your horse is already showing signs of Iris poisoning, diagnosis and treatment are necessary to determine the best treatment. The veterinarian will most likely do a complete physical examination including palpation and auscultation of each vital organ, check and record your horse’s vital signs, and run some diagnostic tests. In addition, the veterinarian may do a lameness assessment with help from the veterinary assistant. Your veterinarian will be looking for abnormalities in your pet’s behavior, walk, and conformity.

Laboratory tests needed will include the general blood tests and urinalysis. However, some veterinarians like to do more extensive tests to rule out other conditions. Some of these may include a liver enzyme culture, creatine kinase (CK), and a packed cell volume (PCV) to determine if your horse is dehydrated.



Treatment of Iris Poisoning in Horses

The treatment for Iris poisoning is similar to other poisonings, which include activated charcoal, gastric lavage, laxative, and fluid therapy to clear out the poisons and hospitalization for observation, if needed.


To decontaminate your horse, the veterinarian will use a gastric tube to administer activated charcoal. This will absorb the poisons that are still in the digestive tract.

Gastric Lavage

The veterinarian will then use the same tube to suction out the contents of the stomach and pump water into the stomach to flush out any plant particles that may be leftover. The veterinarian can examine the stomach contents to verify the plant or plants that were consumed.


Another way to remove any toxins and plant particles left in the digestive system is by giving your horse a laxative. Either magnesium or sodium sulphate is usually used for this purpose. The gastric tube will also be used to administer the laxatives.

Fluid Therapy

To flush out the kidneys and help circulation, the veterinarian will administer intravenous (IV) fluids. This procedure also helps hydrate your horse if your equine is dehydrated from diarrhea.


A 24-hour hospital stay is usually recommended for observing your horse. Many complications that occur will usually happen in the first 24 hours and it is best to have veterinary professionals nearby to provide supportive treatment when needed.



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Recovery of Iris Poisoning in Horses

Your horse has an excellent chance for a full recovery if you get treatment from a veterinarian right away. It is especially helpful if you leave your horse in the hospital overnight to prevent complications. Once you get home, monitor your horse for the next few days to watch for a relapse or other complications. Your veterinarian may want to keep your horse on a bland diet of hay or pelleted food only for several days to let the stomach heal. Be sure to remove any toxic plants and weeds from any area where your horse is allowed to graze to prevent another occurrence.



Iris Poisoning Questions and Advice from Veterinary Professionals

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