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Toxic

Is horse chestnut (conker and buckeye) toxic to dogs? Yes: toxic

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

ASPCA Poison Control+1 (888) 426-443524/7, 365 days a year · A consultation fee may apply · Run by the ASPCA for pet owners and vets.
Pet Poison Helpline+1 (855) 764-766124/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean.

Poison lines in other countries: United Kingdom, Canada, Australia, New Zealand, Belgium, France, JM, PR, Singapore, Switzerland, TT, VI

United Kingdom

Animal PoisonLine+44 1202 50900024 hours a day · A fee applies; their website has the current price · Run by the Veterinary Poisons Information Service for pet owners; for collapse, fits or breathing trouble, call your vet.

Canada

Pet Poison Helpline+1 (855) 764-766124/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean.

Australia

Animal Poisons Helpline1300 869 73824/7 · From A$79 per consultation; their website has the current price · Staffed by poisons information consultants with emergency vet or pharmacy backgrounds.

New Zealand

NZ Animal Poisons Helpline0800 869 73824/7 · Charges apply · The NZ National Poisons Centre does not advise on animals and refers pet owners here.

Belgium

Centre Antipoisons / Antigifcentrum070 245 245Animal questions: weekdays 8:00 to 16:00; weekends and public holidays 10:00 to 16:00 · Free call · Human poison center that also takes animal questions; human emergencies get priority, so call your vet first.

France

CNITV (Centre National d'Informations Toxicologiques Vétérinaires)+33 4 78 87 10 408:30 am to midnight, every day · Veterinary poison center that answers vets and pet owners; call your own vet first if you can.

JM

Pet Poison Helpline+1 (952) 853-171624/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean. This is the number it gives for other Caribbean islands; it also lists a toll-free number for the Caribbean, +1 (877) 416-7319.

PR

Pet Poison Helpline+1 (877) 416-731924/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean; this is its toll-free number for callers in the Caribbean and the US Virgin Islands.

Singapore

Animal Poisons Helpline+65 3106 421624/7 · Ask about the fee when you call · Australia-based animal poison service; this is the Singapore number listed on its site.

Switzerland

Tox Info Suisse14524/7 · Swiss poison center that also tells owners how risky an animal exposure is; from abroad call +41 44 251 51 51.

TT

Pet Poison Helpline+1 (952) 853-171624/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean. This is the number it gives for other Caribbean islands; it also lists a toll-free number for the Caribbean, +1 (877) 416-7319.

VI

Pet Poison Helpline+1 (877) 416-731924/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean; this is its toll-free number for callers in the Caribbean and the US Virgin Islands.

Find an emergency vet

Horse chestnut (conker and buckeye) and dogs: key facts

Verdict: Toxic · Call your vet or a poison line
What it can do: Severe vomiting, diarrhea, restlessness or low energy, dilated pupils and weakness and wobbly walking. All 7
How fast: Within hours
What to do now: Call your vet or a pet poison line now. All steps
Sources: ASPCA Animal Poison Control, Pet Poison Helpline, Dogs Trust. Reviewed 9 October 2026.

What should I do if my dog ate horse chestnut (conker and buckeye)?

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.

Symptoms 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

Guide reviewed 9 October 2026. Page updated 7 November 2026.

General information from the sources above, not a diagnosis. When in doubt, call your vet.