Is Hoary Alyssum Toxic to Dogs and Cats? (2026)

Berteroa incana

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Safe
Safe
Moderate

Quick facts

Toxic to dogsNo
Toxic to catsNo
Toxic to horsesYes
Toxic componentUnidentified (associated with laminitis and limb swelling in horses)
Onset of symptomsWithin 12-24 hours of eating contaminated hay
Indoor / outdooroutdoor

If your pet ate this plant

Both lines are staffed 24/7. A consultation fee applies to each. Do not wait for symptoms to appear before calling.

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Symptoms in horses

  • Limb swelling
  • Laminitis
  • Fever
  • Diarrhea

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What to do

Primarily a hazard when baled into hay rather than fresh pasture; not established as a dog or cat risk. Contact a vet promptly if a horse shows limb swelling after eating hay suspected to contain this weed.

Toxic component and mechanism

The toxic component in Hoary Alyssum is unidentified (associated with laminitis and limb swelling in horses).

What makes this plant different

Hoary Alyssum is a hay-contamination hazard rather than a pasture-grazing one — horses are most commonly affected when this weed gets baled into hay, since drying doesn't reduce its toxicity the way it does for some other plants on this list.

Plant identification

Scientific name
Berteroa incana
Family
Brassicaceae
Also known as
Hoary Alyssum
Typically found
outdoor

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The information on this page is for general informational purposes only and is not a substitute for professional veterinary advice. Plant toxicity data is sourced from the ASPCA Toxic and Non-Toxic Plants database. If you believe your pet has ingested a toxic plant, contact your veterinarian or the ASPCA Animal Poison Control Center (888-426-4435) immediately. Do not wait for symptoms to appear.

Last verified: July 2, 2026 · Cross-referenced with ASPCA Animal Poison Control