PupkeeperToxic
Is horse chestnut (conker and buckeye) toxic to dogs?
Toxic. Conkers and buckeyes can cause severe vomiting and diarrhea, wobbliness and seizures, and can block the gut.
If your dog ate or touched this, call your vet or a pet poison line now
United States
Poison lines in other countries: United Kingdom, Australia, Canada, New Zealand
What to do now
- Call your vet or a pet poison line now.
- Take any conkers away from your dog.
- Keep your dog on a leash where conkers have fallen.
Don't
- Don't make your dog vomit unless a vet tells you to.
Signs to watch for
- Severe vomiting
- Diarrhea
- Restlessness or low energy
- Dilated pupils
- Weakness and wobbly walking
- Tremors
- Seizures or collapse
When signs appear: Within hours
Why
Horse chestnut seeds and leaves contain aesculin and other saponins. They can also cause choking or block the gut.
Sources
- ASPCA Animal Poison Control: Horse Chestnut
- Pet Poison Helpline: Horse Chestnut
- Dogs Trust: Conkers and Acorns
Guide reviewed 9 October 2026.
General information from the sources above, not a diagnosis. When in doubt, call your vet.