Can Dogs Eat Walnuts?
No — walnuts should not be given to dogs. The main danger is MOULD: mycotoxins that form on damp or fallen walnuts cause tremors and seizures. On top of that come high fat, obstruction, and shell risks.
Last reviewed: July 24, 2026
Why are they risky?
The most serious problem with walnuts for dogs is mould toxins. Tremorgenic mycotoxins that develop on walnuts left under a tree, dampened, or stored too long affect the nervous system: tremors, incoordination, agitation, and seizures. Because this can occur even on walnuts that look fine, sorting them by eye is not reliable.
The second risk is fat: walnuts are very fatty, and too many cause vomiting, diarrhea, and pancreatitis. The third is mechanical — whole nuts and especially hard shell fragments can choke or block the intestine. Black walnuts are additionally considered more toxic to dogs.
What to do if your dog ate walnuts
Note how many, shelled or unshelled, and whether they were fresh or stored, then call your veterinarian. Tremors, unsteadiness, agitation, or seizures are an EMERGENCY — go to the clinic without waiting.
Watch for these signs
- Tremors, muscle twitching
- Unsteady walking, stumbling
- Agitation, over-excitement
- Vomiting, diarrhea
- Seizures (mould toxin — emergency)
If you notice any of these, contact a veterinarian without waiting.
Frequently asked questions
Will one walnut hurt my dog?
A single fresh, shelled walnut usually passes with mild digestive upset in most dogs. But you cannot tell whether it carries mould — that uncertainty is exactly why walnuts should not be given at all.
I have a walnut tree in the garden — what should I do?
Fallen walnuts grow mould in damp conditions and are the riskiest form. Collect them regularly and limit your dog's free access under the tree.
What about walnut oil or walnut desserts?
No. Walnut desserts also bring sugar, chocolate, and sometimes xylitol — each a separate risk.
Related answers
Sources
This guide is based on publications from the following veterinary bodies. Where sources differ, we take the more cautious position; the final decision is always your veterinarian's.