Can Dogs Eat Walnuts?
Quick Answer: Walnuts are best avoided. Plain English walnuts are not officially classed as toxic, but they are very high in fat (a pancreatitis risk), can be a choking or blockage hazard, and readily grow molds that make tremorgenic mycotoxins capable of triggering tremors and seizures. Black walnuts are toxic to dogs. There is no nutritional reason to feed walnuts, so it is safest to keep them off the menu.
The Short Answer: Skip the Walnuts
Walnuts fall into the "not worth the risk" category for dogs. A single plain, fresh English walnut swiped off the floor is unlikely to poison a healthy dog, but walnuts are rich, fatty, and prone to spoilage in ways that can cause real harm. There is nothing in a walnut your dog cannot get more safely from a dog-appropriate treat.
The most important caveat is mold. Old, damp, or shell-on walnuts, and any that have fallen from a tree, can carry molds that produce tremorgenic mycotoxins. These toxins act on the nervous system and can cause muscle tremors and seizures within minutes to a few hours. Black walnuts are more dangerous still and are listed as toxic to dogs. If your dog eats moldy or black walnuts, treat it as an emergency and contact your veterinarian, or your nearest emergency vet or an animal poison control center right away.
Why Walnuts Are Risky for Dogs
Rather than a list of benefits, walnuts are better understood as a list of hazards. Here is what makes them a poor choice:
- Prone to toxic mold. Walnuts easily develop molds (including Aspergillus and Penicillium species) that produce tremorgenic mycotoxins and aflatoxin. These can cause tremors, seizures, vomiting, and appetite loss.
- Black walnuts are toxic. The ASPCA lists black walnut (Juglans nigra) as toxic to dogs; moldy black walnuts and their hulls are associated with tremors and seizures.
- Very high in fat. The oils that make walnuts appealing also make them a pancreatitis risk, especially if a dog eats more than a small amount.
- Choking and blockage hazard. Whole walnuts, and especially shell fragments, can lodge in the throat or cause an intestinal obstruction, particularly in small dogs.
- Often salted or seasoned. Packaged walnuts are frequently salted or coated with flavorings such as garlic or onion, which add their own toxicity concerns.
Risks and What to Watch For
If your dog gets into walnuts, keep an eye out for the problems below and note how many were eaten and whether they looked old or moldy.
- Tremorgenic mycotoxin poisoning. The biggest concern with moldy walnuts. Signs can appear within about 15 minutes to a few hours and include muscle tremors, twitching, loss of coordination, restlessness, a high body temperature, and seizures.
- Juglone and GI upset. Black walnuts (and pecans) may contain juglone, which can cause stomach upset, vomiting, and diarrhea.
- Pancreatitis. Because walnuts are so fatty, watch for vomiting, diarrhea, a painful or tense belly, hunched posture, weakness, and loss of appetite.
- Choking or obstruction. Gagging, retching, drooling, repeated unproductive vomiting, or straining can signal a nut or shell stuck in the airway or gut.
- Salt or seasoning effects. Heavily salted or garlic- and onion-seasoned walnuts add extra risk on top of the nut itself.
Safer Ways to Handle Walnuts
The safest approach is not to feed walnuts at all and to make sure your dog cannot help themselves. A few practical steps:
- Do not offer walnuts as a treat. Skip them in raw form and in baked goods like banana bread, brownies, and cakes, which also often contain other dog-unsafe ingredients.
- Store them out of reach. Keep bags of walnuts in a sealed container in a closed cupboard, not in a low bowl on the counter or coffee table.
- Clear fallen nuts from the yard. If you have a walnut tree (especially a black walnut), rake up dropped nuts, hulls, and debris before they mold, and supervise walks near these trees.
- Secure your compost and trash. Moldy nuts and food scraps in open compost or bins are a common source of tremorgenic mycotoxin poisoning.
- Have a plan if your dog sneaks one. Note the type of walnut (English vs. black), the amount, and whether it looked moldy, then call your veterinarian or an animal poison control center for advice. These are general guidelines, so check with your vet about your own dog's needs.
Safer Alternatives to Walnuts
If you want to share a snack, reach for something low-fat and dog-friendly instead. Good options, offered in moderation, include:
- Carrot sticks or baby carrots
- Apple slices with the seeds and core removed
- Blueberries
- Plain cooked or canned pumpkin (no spice blends or sweeteners)
- Cooked, plain green beans
- A little plain, unsalted, xylitol-free peanut butter smeared on a lick mat
- Treats made and portioned specifically for dogs
As a rule of thumb, treats of any kind should make up no more than about 10% of your dog's daily calories, with the rest coming from a complete and balanced diet. These are general guidelines, so check with your vet for your dog's needs.
When to Worry: If Your Dog Eats Walnuts
One or two fresh, plain English walnuts in an otherwise healthy dog usually cause nothing worse than mild stomach upset, if anything. The situation is more serious when a dog eats a larger amount, eats black walnuts, or eats walnuts that are old, damp, or moldy.
Call for help promptly if your dog ate moldy or black walnuts, ate a large quantity, is a small breed, has a history of pancreatitis, or shows any signs such as tremors, twitching, unsteadiness, seizures, repeated vomiting, or belly pain. When in doubt, do not wait for symptoms to worsen. Contact your veterinarian, or your nearest emergency vet or an animal poison control center right away, and try to tell them the type and amount of walnut eaten.
Frequently Asked Questions
Are a few walnuts dangerous for my dog?
A single fresh, plain English walnut is unlikely to seriously harm a healthy dog and may cause only mild stomach upset. Even so, walnuts are not recommended because they are high in fat and easily mold. If your dog ate more than a couple, ate black or moldy walnuts, or seems unwell, call your veterinarian.
What happens if my dog eats a moldy walnut?
Moldy walnuts are the biggest concern. They can contain tremorgenic mycotoxins that affect the nervous system, and even one or two can trigger muscle tremors, loss of coordination, and seizures, sometimes within 15 minutes to a few hours. This is an emergency, so contact your veterinarian, or your nearest emergency vet or an animal poison control center right away.
Are black walnuts more dangerous than English walnuts?
Yes. Black walnuts (Juglans nigra) are listed by the ASPCA as toxic to dogs, and their nuts and hulls are especially likely to cause tremors and seizures when moldy. They may also contain juglone, which can cause vomiting and diarrhea. Keep dogs away from black walnut trees and any dropped nuts or hulls.
My dog ate walnut in banana bread or a cake. What now?
Watch closely and call your veterinarian for advice, especially if the baked item was large or contained other risky ingredients like chocolate, raisins, or xylitol. Baked goods add fat and sugar on top of the walnut, which raises the chance of stomach upset or pancreatitis. Note how much your dog ate so your vet can gauge the risk.
Can puppies or small dogs eat walnuts?
It is best to keep walnuts away from puppies and small dogs entirely. Their smaller size means a given amount of fat, toxin, or a single whole nut poses a proportionally greater risk of pancreatitis, poisoning, choking, or intestinal blockage. Offer a small, dog-safe treat instead.
