Are horse chestnuts toxic to dogs?
Horse chestnuts (buckeyes), the shiny brown nuts from the park, are toxic to dogs (ASPCA). They can cause vomiting, diarrhea, wobbliness and seizures, and swallowed whole they can block the gut (Pet Poison Helpline).
Good to know: Don’t confuse them with sweet chestnuts (Castanea), a different genus (Pet Poison Helpline). ASPCA lists the American chestnut as non-toxic, but none of our sources recommends chestnuts as a treat. Don’t use them as toys either.
Did your dog eat some?
Call your vet or an emergency vet clinic right away, even if your dog seems fine. Tell them what your dog ate, how much and when.
- ASPCA Animal Poison Control: (888) 426-4435 (a fee may apply)
- Pet Poison Helpline: (855) 764-7661 (a fee may apply)
- Don’t make your pet vomit unless a vet tells you to.
Better choices, for example
Questions
My dog ate horse chestnuts. What should I do?
Call your vet or an emergency vet clinic right away, even if your dog seems fine. You can also call ASPCA Animal Poison Control at (888) 426-4435 or the Pet Poison Helpline at (855) 764-7661 (a fee may apply). Don’t make your dog vomit unless a vet tells you to.
Are horse chestnuts toxic to cats?
Yes, toxic. Horse chestnuts (buckeyes), the shiny brown nuts from the park, are toxic to cats (ASPCA). They can cause vomiting and diarrhea, and swallowed whole they can block the gut (Pet Poison Helpline).
Sources
- ASPCA Toxic and Non-toxic Plants – Horse Chestnut
- Pet Poison Helpline – Horse Chestnut
- Pet Poison Helpline – Buckeye
- ASPCA Toxic and Non-toxic Plants – Chestnut (non-toxic)
Last checked: October 2026