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Is Walnut Tree 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, walnut is toxic to dogs. Fresh nuts and leaves cause stomach upset, and moldy fallen walnuts can trigger severe tremors and seizures.

Also known as: English Walnut, Black Walnut · Juglans spp.

What makes it toxic

Juglone and phenolic compounds in nuts, hulls and foliage, plus tremorgenic mycotoxins from Penicillium mold that grows on decaying fallen walnuts.

Warning signs to watch for

Vomiting and diarrhea after fresh nut or leaf eating; moldy husk ingestion brings muscle tremors, panting, hyperthermia and seizures within hours.

What to do if your dog eats it

Call your vet for fresh nut ingestion; treat any suspected moldy walnut eating as an emergency since tremorgenic poisoning progresses fast and needs hospital support.

Common questions

My dog picked up moldy black walnuts in the yard — is that serious?

Yes, very. Moldy black walnut husks have caused documented tremor and seizure episodes in dogs. Go to the vet immediately.

Can dogs eat plain walnut kernels from my baking shelf?

Not recommended. Walnuts are fatty and prone to mold, and English walnuts themselves cause GI upset in dogs. Choose pet treats instead.

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.