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Can Dogs Eat Walnuts?

walnuts on table

Technically, most English walnuts are not toxic to dogs (and once the shell or husk is removed, they pose less of a health risk), but that doesn’t mean you should offer them to your pet. Never offer your dog black walnuts or moldy English walnuts because they are toxic to dogs, and always keep shells and husks out of reach because they can cause gastrointestinal perforation or obstruction. If you happen to drop an English walnut without the shell on the floor and your dog gobbles it up before you can grab it, they’ll most likely be okay, but there are some warning signs to look out for, too. As always, consult your veterinarian with any concerning behavior that follows ingesting food.

Walnuts can be a tasty and healthy snack for humans; they are rich in nutrients and packed with protein. But just because they are good for humans doesn’t make them an appropriate snack for your pup.   

Dogs have a different digestive system than humans. Their gastrointestinal system can’t process the unnecessary calories and high fat content in walnuts. Not only are most of the health benefits of walnuts unavailable to your dog, but there are long-term concerns from eating too many nontoxic walnuts, such as obesity or even pancreatitis. 

Eating walnuts can potentially cause immediate problems for your dog, such as ingesting toxic mold or experiencing gastrointestinal blockage or perforation. These are all reasons why most nuts are not recommended for your dog. 

Are there health benefits of walnuts for dogs?  

Dogs are their healthiest when they have a well-balanced, high-protein, low-fat and low-carbohydrate diet with all essential vitamins and minerals as provided by a high-quality, commercially available dog food. Like most nuts, walnuts are high in fat and composed of fibers that the canine digestive system is not adapted to absorb. A few nuts consumed on accident are unlikely to be a problem, but even nontoxic English walnuts can cause gastrointestinal distress, obesity and pancreatitis in your pet when eaten regularly or in large quantities. 

Contact your vet immediately if signs of vomiting, diarrhea, constipation or even a change in behavior arise after your dog ingests walnuts, as these could be symptoms of a serious health condition.

Pancreatitis in dogs is a condition that stems from an overload of fats in their diet, causing the pancreas to become inflamed. Acute cases require treatment from a veterinarian. Chronic cases can reduce the length and quality of your dog’s life and make taking care of them more difficult.   

Toxic walnuts can also make your dog sick or even lead to death if untreated. All nuts run the risk of containing some molds or fungus on them, and this mold can make walnuts toxic to dogs.  

While it’s less likely for mold to occur in store-bought walnuts, there is always a risk.   Mold is more likely to be present on old or raw nuts—if the nuts have been sitting in a bag in the back of your pantry for too long, they run a higher risk of having potentially developed toxic mold. 

There are also two types of walnuts, and the difference is important for your dog’s safety. English walnuts are the type most commonly available at the grocery store; they usually aren’t toxic to dogs in small quantities. The other type of walnut is the black walnut, which can potentially be very dangerous to dogs. Black walnuts are native to the northeastern U.S.A. and Canada, and they can carry a poisonous substance called juglone, which is secreted by the roots of the tree. Juglone is toxic to horses and dogs, but not cats for some reason.  

If your dog has a reaction from eating a moldy walnut or a black walnut, the symptoms can include vomiting, tremors and dog seizures. If you see any of these signs, call your veterinarian, an emergency veterinarian or the Pet Poison Helpline immediately because it could be fatal if left untreated. 

The other potential health concern walnuts pose for dogs is intestinal blockage, which can occur when a walnut or shell gets lodged in the dog’s system and cannot appropriately pass through their intestines. Walnut shells can also break into small pieces and lead to gastrointestinal perforation. Symptoms of intestinal blockage in dogs include frequent vomiting, loss of appetite, lethargy, bloated abdomen, abdominal discomfort, weakness and depression. 

If you suspect your dog is experiencing any type of abnormal behavior or any of the symptoms listed above, consult your veterinarian immediately. These health concerns may require surgery and could be fatal if not addressed right away. 

How to feed walnuts to your dog  

As discussed above, it’s not recommended to feed walnuts to your dog.   

FAQs about walnuts and dogs 

While many types of nuts are not considered toxic, they are not an appropriate treat for your dog and can have many concerning side effects, some of which can be fatal. Walnuts can potentially contain mold or fungus, which can be toxic to dogs if ingested. Black walnuts also contain a substance called juglone, which is toxic to dogs.

Also, most nuts come in shells, which are often hard and hazardous for your dog if accidentally consumed. Shells can be a choking hazard and cause gastrointestinal blockage, and broken pieces can slice your dog's digestive tract as they move through.

Lastly, there is one member of the nut family you especially want to keep far away from your dog—the macadamia nut. Macadamias are highly toxic to dogs and can lead to weakness in the back legs, vomiting and diarrhea.  

If you suspect your dog is suffering from pancreatitis, consult with a veterinarian right away. Not only can they provide potentially life-saving treatment, but they can also offer ways to help keep your dog comfortable.   

While it’s unlikely, ingesting English walnuts can be fatal. Symptoms to watch for if your dog accidentally consumes a nontoxic nut are choking and intestinal blockage or perforation.

Other dangers include a toxic reaction to mold or other substances commonly found on walnuts. Mold is more likely to grow on old walnuts or raw walnuts collected directly from orchards, but it can be found on any walnut.  

Black walnuts are a type of walnut native to the northeastern United States and Canada. This type of walnut contains a toxin called juglone, which is toxic to dogs if ingested.

If you suspect your dog has ingested a whole walnut, a piece of walnut shell or a toxic walnut, call your veterinarian immediately for instructions.  

The answer to this question depends on many factors. Contact your vet to review the situation and develop a move-forward plan as soon as possible. 

A whole walnut shell is a large object for a dog of any size to swallow and may result in intestinal blockage and other symptoms of gastrointestinal distress. Broken walnut shells can severely cut or scratch the internal lining of your dog's gastrointestinal system, and mold found on the nut or shell can contain potentially fatal toxins.

In all instances, it’s highly recommended to contact your veterinarian, an emergency veterinarian or the Pet Poison Helpline right away to decide the best course of action for your situation.

While there’s no specific number on how many walnuts a dog can or can’t eat before symptoms of illness present, walnuts are not an appropriate treat or snack for your dog. Your dog doesn't digest nuts the same way humans do, and when eaten regularly or in large quantities, walnuts can cause gastrointestinal blockage, distress, obesity and pancreatitis in dogs. Due to the risk walnuts can impose on your dog’s health, it is not recommended to intentionally offer them walnuts as a treat.

Salted walnuts are not good for dogs. Like most nuts, walnuts don’t typically agree with your dog’s digestive system. The salt is even worse and can lead to dehydration and cell and organ damage if eaten in large quantities or too regularly.

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Reviewed by Petco’s Animal Care, Education and Compliance (ACE) Team

Petco’s ACE team is a passionate group of experienced pet care experts dedicated to supporting the overall health & wellness of pets. The ACE team works to develop animal care operations and standards across the organization and promote proper animal care and education for Pet Care Center partners and pet parents, while also ensuring regulatory compliance.