The Complete Guide to Dogs Eating Walnuts: Toxic or Good?

This content was reviewed and fact-checked by veterinarian Dr. Aukse Caraite, DVM.

No, dogs should not eat walnuts. While they may appear to be a nutritious snack for humans and dogs can safely eat a few walnuts (only the right kind), especially if they are store-bought and unsalted, walnuts are not the ideal choice for your dog —especially moldy ones—can be harmful to dogs and pose several health risks, including gastrointestinal distress, pancreatitis, and even neurological symptoms. Even fresh walnuts are high in fat and may lead to stomach upset or more severe issues if consumed regularly. But what about walnut butter? Are certain walnut types more dangerous than others? Can one walnut really make a dog sick? This guide will explore the risks of walnuts, signs of toxicity, and what to do if your dog accidentally eats one.

Are Walnuts Good For Dogs?

No, walnuts are not recommended for dogs. While not always immediately toxic like grapes, walnuts—especially moldy ones—can cause serious health problems.

Why Are Walnuts Toxic to Dogs?

Walnuts can be harmful to dogs for two main reasons: the type of walnut and the presence of mold growth on the nut or hull.

This mold can produce tremorgenic mycotoxins, such as Penitrem A, which are potent neurotoxins for dogs. These toxins can cause symptoms ranging from vomiting and muscle tremors to seizures, hyperthermia, and even death in severe cases. Moldy walnuts and their husks, particularly those that have fallen to the ground and decomposed, are the most dangerous. The risk is higher after rainy periods, when mold growth is more likely.

What The Science Says

A retrospective study published in the Journal of the American Veterinary Medical Association analyzed 93 cases of dogs exposed to black walnut (Juglans nigra) wood, nuts, or hulls.^[1] The study found that:

1. Vomiting: Ingestion of black walnut nuts or hulls most commonly caused spontaneous vomiting (observed in 48% of cases).

2. Neurologic or musculoskeletal side effects: Tremors or incoordination were significantly more common in dogs that ingested black walnut wood (93%) than those that ingested nuts or hulls (23%).

3. Neurological signs: The relative risk of developing neurological signs was approximately four times higher after ingesting wood compared to nuts or hulls.

The study concluded that ingestion of black walnut wood and nut components results in two distinct clinical syndromes, with nut ingestion primarily causing gastrointestinal upset and wood ingestion causing neurologic symptoms.

Toxic Dosage

There is no universally established “safe” dosage of walnuts for dogs, because even small amounts can be harmful—especially if the walnuts are moldy or if they are black walnuts.

There is no universally established “safe” dosage of walnuts for dogs. Even small amounts of walnuts can pose health risks to dogs, especially depending on the type. Moldy walnuts are the most dangerous—just one or two can trigger serious symptoms due to the presence of tremorgenic mycotoxins, which affect the nervous system. Black walnuts are also highly toxic; as little as 0.1 ounces per pound of body weight (about 2.8 grams per pound) may be enough to cause toxicity. English walnuts are less toxic but still risky. Ingesting more than 0.5 ounces per 2 pounds of body weight (about 7 grams per kilogram) can lead to gastrointestinal upset or pancreatitis, especially in smaller dogs. Lastly, walnut shells aren’t chemically toxic but can cause serious physical harm—such as intestinal blockages or choking—at any amount. Because walnut toxicity depends heavily on the dog’s size, the type and freshness of the nut, and whether mold is present, it’s safest to avoid giving walnuts to dogs altogether.

Symptoms of Walnut Toxicity

The following symptoms may indicate a bad reaction to walnuts

Early signs (6–12 hours post-ingestion)

Progressive symptoms

• Seizures or muscle tremors (especially from moldy walnuts)
• Fever or increased body temperature
• Weakness or collapse
• Abdominal pain or bloating
• Signs of pancreatitis (severe vomiting, hunched posture, refusal to eat)

If left untreated, ingestion—particularly of moldy or black walnuts—can lead to life-threatening neurological complications, pancreatitis, or intestinal obstruction.

Immediate Actions if Your Dog Eats Walnuts

Dogs showing worsening symptoms, such as blood in their vomit or stool, difficulty breathing, weakness, or collapse, should be taken to the veterinarian immediately.

1. Contact a veterinarian immediately: Even if your dog seems fine, contact your veterinarian or an emergency pet poison hotline right away. This includes services such as the ASPCA Animal Poison Control Center at 1-888-426-4435 or the Pet Poison Helpline at 1-855-764-7661. If you can’t reach your vet, you can chat live with a veterinary professional via our online vet chat or video chat support (24 hours a day, 7 days a week). You can also schedule an at-home veterinary appointment with The Vets, a mobile veterinary service that provides at-home vet care nationwide for just about everything.

2. Do not induce vomiting without guidance: Avoid inducing vomiting unless instructed by a veterinarian. Inducing vomiting can sometimes worsen the situation if not done correctly.

3. Gather important information: When speaking to a vet, provide:

• Quantity consumed (estimate if unsure)
• Time of ingestion (how long ago the walnuts were eaten)
• Dog’s weight and breed (to assess potential risk)

4. Follow veterinary instructions: The vet may suggest monitoring at home or emergency treatment at the clinic.

• Keep your dog calm and prevent them from eating anything else.
• Be prepared to transport your dog to the vet quickly if advised.
• Bring any remaining walnuts or packaging to help the vet assess the situation.

How Veterinarians Diagnose & Treat Walnut Poisoning

Veterinarians diagnose walnut poisoning in dogs based on a history of ingestion, observed symptoms, and diagnostic testing. Blood tests (serum biochemistry) may be used to assess for elevated liver enzymes, pancreatic inflammation, or signs of systemic toxicity. If moldy walnuts were ingested, neurological signs may prompt testing for tremorgenic mycotoxins. Urinalysis and imaging may also be performed to rule out gastrointestinal blockage from shells. Treatment focuses on rapid decontamination and supportive care. If ingestion was recent, vomiting may be induced, followed by administration of activated charcoal to limit toxin absorption. Intravenous fluid therapy is often started to support hydration, flush toxins, and prevent complications such as pancreatitis or toxin buildup. Additional treatments—including anti-seizure medication, anti-nausea drugs, and muscle relaxants—may be used depending on the symptoms.

Regular monitoring of neurological function, hydration status, and organ response is essential. In severe cases involving mold toxicity, hospitalization and intensive care may be required. Early veterinary intervention improves the chances of full recovery, but outcomes depend on the amount and type of walnut ingested and the speed of treatment.

Estimated Vet Bill for Walnut Poisoning Treatment

Total Estimated Cost:

• Mild Cases (Early Decontamination Only): $300 – $800
• Moderate Cases (IV Fluids, Seizure Control, Monitoring): $1,000 – $2,500
• Severe Cases (Hospitalization, Neurological Treatment, Pancreatitis or Mold Toxin Management): $3,000 – $8,000+

💡 Pet insurance consideration: If a dog has pet insurance, some costs may be covered, but owners should check their policy details. Without insurance, emergency vet care can be costly. We recommend getting pet insurance for financial protection against unexpected medical emergencies, ensuring your pet receives the best possible care without the burden of high out-of-pocket expenses. Check out our best pet insurance guide to find a suitable plan for your pet.

At-Home Tests & Prevention Tips to Avoid Poisoning Dogs

Safe Alternatives to Walnuts

Here’s a list of alternatives to walnuts that are safe for dogs

Frequently Asked Questions

The Bottom Line

While walnuts offer health benefits to humans, they are not a safe snack for dogs. From their high fat content to the risk of mold-related toxins and the dangers posed by black walnuts and shells, the potential health complications far outweigh any nutritional value. Ingestion can lead to gastrointestinal upset, pancreatitis, or even neurological symptoms—especially if the nuts are spoiled or moldy. If your dog accidentally eats a walnut, especially one that’s moldy or from an unknown source, contact your veterinarian immediately. When it comes to your dog’s health, it’s always better to be cautious—stick to dog-safe treats and leave the walnuts out of their bowl.

If you’re looking for other healthy snack options, check out the best dog treats to find safe and nutritious alternatives.

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Sources

Canine Bible uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process and product review methodology to learn more about how we fact-check, test products, and keep our content accurate, reliable, and trustworthy.

1. Clinical signs associated with ingestion of black walnut tree (Juglans nigra) wood, nuts, and hulls in dogs: 93 cases (2001-2012)