Is Russian Knapweed Toxic to Dogs and Cats? (2026)
Centaurea repens
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Quick facts
| Toxic to dogs | No |
|---|---|
| Toxic to cats | No |
| Toxic to horses | Yes |
| Toxic component | Repin (a sesquiterpene lactone, causes a specific fatal neurological disease in horses) |
| Onset of symptoms | Develops after weeks to months of continuous grazing — the same "chewing disease" caused by Yellow Starthistle |
| Indoor / outdoor | outdoor |
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
- Facial muscle spasms
- Difficulty eating and drinking
- Lip and tongue paralysis
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What to do
A chronic grazing-exposure risk for horses (nigropallidal encephalomalacia); not established as a dog or cat hazard.
Toxic component and mechanism
The toxic component in Russian Knapweed is repin (a sesquiterpene lactone, causes a specific fatal neurological disease in horses).
What makes this plant different
Russian Knapweed causes the same 'chewing disease' neurological condition in horses as its relative Yellow Starthistle — both are invasive rangeland weeds that pose a purely chronic, grazing-based risk rather than a single-bite hazard.
Plant identification
- Scientific name
- Centaurea repens
- Family
- Compositae
- Also known as
- Russian Knapweed
- Typically found
- outdoor
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Related plants
African Daisy
Gerbera jamesonii
Barberton Daisy
Gerbera jamesonii
Barnaby's Thistle
Centaurea solstitialis
Blue Daisy
Felicia amelloides
Chamomile
Anthemis nobilis
Last verified: July 2, 2026 · Cross-referenced with ASPCA Animal Poison Control