Jimsonweed Poisoning in Horses

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Last updated on
4 min read

Key takeaways

Jimsonweed toxicosis is a rare and potentially life-threatening condition in horses that occurs from ingestion of jimsonweed (Datura stramonium).

  • Jimsonweed plants contain a wide array of toxins that cause abdominal pain, dilated pupils, difficulty breathing, reduced appetite, and collapse
  • Diagnosis of jimsonweed toxicosis is based on history of exposure and symptoms
  • There is no antidote for jimsonweed toxicosis making treatment options limited
  • Treatment is  focused on removal of the plants from the stomach and symptomatic care
  • Prognosis varies widely and depends on the amount of toxin ingested, as well as the timing of treatment
  • Horses with severe symptoms have a guarded prognosis
  • Due to limited treatment options, prevention is essential in ensuring safety for horses who are at risk of exposure to jimsonweed
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A closer look: Jimsonweed Poisoning in Horses

Jimsonweed is a poisonous plant found in temperate climates all over the world. There are multiple toxins present in the plant which affect the nervous and digestive systems.

Ingestion of large amounts of jimsonweed can be life-threatening and must be treated as an emergency. If ingestion is suspected, prompt removal of the source is paramount.

Timely medical attention is crucial in ensuring a positive outcome.

Risk factors

As with all types of poisoning, the quantity of toxin ingested impacts how severe the outcome is.

Jimsonweed toxicosis is rare in horses. The plant is unpalatable and has an unpleasant odor, so horses tend not to eat it if they encounter it. There is a higher risk of poisoning during periods of drought, when other pasture forage may be limited.

Possible causes

Jimsonweed toxicosis is caused by the ingestion of any part of the jimsonweed plant. Datura stramonium contains over sixty kinds of toxins which primarily affect the gastrointestinal and nervous systems.

Main symptoms

Testing and diagnosis

A horse presenting symptoms of jimsonweed toxicosis generally undergoes the following diagnostics:

  • History of exposure
  • Physical examination
  • Identification of toxic plants in pasture, feed, or stomach contents

Steps to Recovery

Currently, there is no antidote or definitive treatment for jimsonweed toxicosis. Treatment is of a symptomatic and supportive nature and includes:

  • Activated charcoal to prevent further toxin absorption
  • Gastric lavage to remove the plants from the stomach
  • Elimination of access to toxin source
  • Pain medication to reduce colic symptoms
  • Anti-seizure medications

Note: always consult a veterinarian before administering medication, including activated charcoal.

Most horses diagnosed with jimsonweed toxicosis are able to recover fully once the source of the toxin is removed and symptoms resolve with appropriate supportive care. Most horses recover within hours to days.

Prognosis varies from guarded to poor. If animals are left to graze on jimsonweed-infested pastures and are not provided with alternative uncontaminated feed after developing symptoms, the risk of severe poisoning or recurrence is high. As the toxicosis worsens, the prognosis becomes guarded due to severe symptoms.


Jimsonweed toxicosis is not contagious.

Due to limited treatment options, prevention is of fundamental importance. Prevention strategies include:

  • Removal of jimsonweed from pastures
  • Providing proper access to alternative, uncontaminated feed sources
  • Inspection of feed prior to feeding

Is Jimsonweed Poisoning in Horses common?

Jimsonweed toxicosis is rare in horses. Horses tend not to feed on jimsonweed due to its impalpability and unpleasant smell.

Typical Treatment

  • Activated charcoal
  • Removal of toxin source
  • Pain medication

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