Mustard Plants Poisoning in Horses

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

Most common symptoms

Anemia / Diarrhea / Lethargy / Mouth Salivation / Pain / Weakness


0 Veterinary Answers

Most common symptoms

Anemia / Diarrhea / Lethargy / Mouth Salivation / Pain / Weakness

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

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What is Mustard Plants Poisoning?

The mustard plant belongs to the Brassicaceae family along with many other plants.  It produces the toxin known as glucosinolate which interferes with the body absorption of certain products.  Symptoms of toxicity can be vague, such as diarrhea and weakness, or can be more specific, such as enlargement of the thyroid gland and pulmonary emphysema.  Your veterinarian should be alerted of your horse’s condition immediately so she can begin her diagnosis and the detoxification process as soon as possible.  There is no antidote to mustard plant intoxication but she can offer him supportive treatment.

Ingestion of mustard plant can be toxic to your horse.  If he is acting abnormally, experiencing any of the symptoms listed below, or if you witnessed him ingesting the mustard plant, you should contact your veterinarian.

Symptoms of Mustard Plants Poisoning in Horses

Symptoms may include:

  • Diarrhea
  • Abdominal pain
  • Excessive salivation
  • Acute pulmonary emphysema 
  • Interstitial pneumonia 
  • Enlargement of thyroid gland
  • Weakness
  • Altered respiratory rate
  • Recumbency 
  • Coma 
  • Death 


The mustard plant scientifically belongs to the Brassicaceae family with the scientific name of Brassica species.  There are a variety of species naturally grown causing the species name to vary.  Commonly, it can be known as white mustard, black mustard, or yellow Indian mustard.

Causes of Mustard Plants Poisoning in Horses

Mustard plants produce glucosinolate toxins and when ingested, causes toxicosis in your horse.  This toxin is also known as mustard oil glycosides or thioglucosides.  Some of the toxins can be found in the seeds and foliage of the plants.  The toxin competes with and prevents the proper uptake of iodide in the body system.

Diagnosis of Mustard Plants Poisoning in Horses

To begin her diagnosis, your veterinarian will start by performing a full physical exam.  She will make note of all of your horse’s symptoms and get details from you about when they started and if they have been getting worse.  The smallest detail may help her rule out other possible causes of his symptoms.   

She will want to perform lab work so she can check his organ values and levels in his blood.  She will suggest a complete blood count (CBC) and chemistry panel to check for abnormalities.  Depending on the results, she may want to run more in depth blood related tests.  Blood testing for the assay of glucosinolate can verify the type of toxin your horse is being affected by.  Blood work to test metabolic end products may also be recommended for evaluation of his levels.  

If your horse is having diarrhea, she will run a series of fecal tests to check for possible causes such as intestinal parasites or bacterial overgrowth.  If this is in addition to abdominal pain, she may want to take a radiograph to check for any type of blockage, injury, or malformation of your horse’s gastrointestinal tract.

If your horse is experiencing breathing difficulties and she cannot confirm the cause via auscultation alone, she may want to take radiographs to check his lungs for air, fluid, masses, or other possible abnormalities.  

There may be other tests your veterinarian will want to run in order to rule out other possible causes of your horse’s ailment.  Of course, if your horse dies you can request a necropsy in order to determine the cause.  This will give you a complete diagnosis to ensure none of your other horses suffer from the same illness.  


Treatment of Mustard Plants Poisoning in Horses

There is no exact treatment your veterinarian can offer your horse.  She can provide supportive therapies and keep your horse comfortable.  You will need to keep your horse stalled in order to closely monitor him and to keep him comfortable during treatments.  Additional therapies will be determined by the symptoms your horse is experiencing.  She will treat symptomatically as symptoms appear.   

You will need to start by finding and removing the source of the mustard plant immediately to prevent further ingestion.  The longer your horse ingests it, the more severe his symptoms will become.    You should change his feed to something of a pellet form in case the mustard plant source is unknowingly in his hay.

She will start fluid therapy to ensure your horse stays hydrated and to keep his liver, kidneys, and urinary tract flowing.  This will also force his body to flush the toxin from his system quicker and more efficiently than without it.  If he is experiencing breathing difficulties, medication and oxygen therapy may be administered in order to provide better oxygen absorption.

Recovery of Mustard Plants Poisoning in Horses

If a small amount of mustard plant was ingested and symptoms treated quickly, prognosis of recovery can be fair to good.  However, the larger the amount ingested and the frequency will all affect his recovery status.  It is best if you can prevent ingestion from occurring in the first place. If you know you have mustard plant on your property get rid of it.  You may need to buy hay from elsewhere or give him a pellet diet in the meantime.  Death from mustard plant ingestion can occur and should be avoided in any way possible.

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Mustard Plants Poisoning Questions and Advice from Veterinary Professionals