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Is Horse Chestnut Toxic to Dogs?

☠️ ToxicSeverity: Moderate
✅ Cross-checked against veterinary poison-control guidance · Oct 2026 audit
⚠️ Educational info only. If your pet just chewed something and looks unwell, skip the reading and call your vet or Pet Poison Helpline (US): (855) 764-7661.
Yes, horse chestnut is toxic to dogs. Conkers dropped in autumn are the main hazard, and chewed conkers cause vomiting, tremors and sometimes worse.

Also known as: Conker Tree, Aesculus · Aesculus hippocastanum

What makes it toxic

Aesculin and aescin saponins concentrated in the conkers and seedlings, acting as gastrointestinal and nervous system poisons.

Warning signs to watch for

Vomiting, diarrhea, drooling, lethargy and abdominal pain within hours; heavier ingestions bring tremors, incoordination and collapse.

What to do if your dog eats it

Note how many conkers were eaten and call your vet or a poison hotline promptly. Vomiting induced early at a clinic improves the outlook; tremors mean ER.

Common questions

My dog plays with conkers — is chewing one enough to poison him?

Chewing releases the toxins, and a swallowed conker also risks intestinal blockage. Discourage conker games and call the vet for any confirmed chewing.

How fast do conker poisoning signs appear?

Usually within one to four hours. If several hours pass with no vomiting or drooling after a suspected conker, keep watching for a full day.

More plants checked for dogs

Pothos☠️ ToxicYes, pothos is toxic to dogs. Chewing any part of the vine releases calcium oxalate crystals thaAloe Vera⚠️ Mildly ToxicAloe vera is mildly to moderately toxic to dogs. The skin and latex layer of the leaf contain coSpider Plant✅ Non-ToxicNo, spider plants are non-toxic to dogs. A dog that nibbles the arching leaves is not at risk ofEaster Lily⚠️ Mildly ToxicEaster lilies are only mildly toxic to dogs — they usually cause stomach upset, not the fatal kiSago Palm☠️ ToxicYes — sago palm is severely toxic to dogs, with a documented fatality rate around 50% when untreBoston Fern✅ Non-ToxicNo, Boston ferns are non-toxic to dogs. Chewing a frond will not poison your dog.

This page is general educational information, not a substitute for professional veterinary advice. Every pet is different — if your animal ate something concerning, contact your veterinarian or a pet poison hotline right away. Checking what your pet can eat? Visit our sister site SafeOrToxic.