Walnuts sit on the avoid list for dogs
Avoid
There is no walnut form recorded as safe for dogs: walnuts are an avoid, and moldy or black walnuts are the most hazardous of them.
Not worth offering as normally served.
No. Walnuts are on the avoid list for dogs and should not be fed on purpose. They are high in fat, and moldy or black walnuts carry a tremorgenic mold toxin risk, with some walnut types treated as specifically hazardous. If your dog eats a large amount or shows symptoms, contact a veterinarian.
- Unsafe form or part
- walnuts, especially moldy or black walnuts
- Preparation
- not recommended
- Deliberate feeding
- No — this is not a food to offer
- Hazard level
- 3 of 4
If your dog has already eaten walnuts
Do not intentionally feed until form/amount is clarified. If a large amount was eaten or symptoms occur, contact a veterinarian.
- ASPCA Animal Poison Control Center: (888) 426-4435 — 24/7, 365 days a year. A one-time consultation fee applies; the ASPCA does not publish the amount on this page.
Sources: ASPCA, PetMD, Merck Veterinary Manual. Evidence grade B+. Last verified 2026-09-07. Dataset 2026.09.
Which form of walnuts the sources actually cleared
This verdict covers walnuts as a food, and the record singles out moldy walnuts and black walnuts as the forms of most concern. Nothing in the record names a walnut form that is cleared for dogs, so there is no shelled, unsalted or plain version listed as the acceptable option. The record also does not break out walnut pieces baked into other foods, walnut butter, or walnut oil as separate cases, so it gives you no basis to treat any of those as different from the whole nut.
Preparing walnuts for a dog
The preparation rule recorded for walnuts is simply that feeding them is not recommended. No shelling, roasting, chopping or portioning step is listed, and that absence is the point: preparation is not what makes walnuts an avoid. Because no safe walnut form is recorded either, there is nothing to prepare toward. Treat the entry as a reason to keep walnuts out of reach and off the treat list rather than a recipe to adjust.
What actually goes wrong
- high fat
- mold-related tremorgenic toxin risk
- some walnut types are specifically hazardous
Three risks are recorded. Walnuts are high in fat. Walnuts that have gone moldy can carry tremorgenic mold toxins, meaning the tremor-causing kind, which is why a mold-affected nut is treated as worse than a sound one. And some walnut types, black walnuts among them, are flagged as specifically hazardous rather than merely fatty. The recorded response to an ingestion is not to feed walnuts intentionally until the form and amount are clear, and to contact a veterinarian if a large amount was eaten or symptoms appear.
What these sources do not settle
The record grades the evidence B+ and leaves several things open. It sets no amount that counts as a large amount, no weight-based threshold, and no treat allowance. It lists no medical conditions that raise the risk further, and it does not spell out which walnut types beyond black walnuts are the specifically hazardous ones. Those gaps are for your veterinarian, not for guesswork.
Sources and review
- ASPCA — People Foods to Avoid Feeding Your Pets (grade A, retrieved 2026-09-07)
- PetMD — What Can Dogs NOT Eat? (grade B+, retrieved 2026-09-07)
- Merck Veterinary Manual — Overview of Mushrooms Toxic to Animals (grade A, retrieved 2026-09-07)
Verdict last verified 2026-09-07. How this site handles sourcing and corrections is set out in the editorial policy, and every reference the site relies on is listed on the sources page.
This page is reference material, not veterinary advice. A dog with a medical condition, a prescription diet or a suspected ingestion needs a veterinarian or a poison control centre, not a web page.
We research and check what we publish, but we do not warrant that any figure, date, price, or statement is accurate, complete, or current, and we accept no liability for any loss, cost, injury, or other harm arising from the use of this site. Use it as one reference among several. You remain responsible for your own decisions and for your dog's care - confirm anything that matters with a licensed veterinarian or another qualified professional before you act on it. Full disclaimer.