Can Dogs Eat Walnuts? When Are Walnuts Toxic To Dogs, And Why?

Can dogs eat walnuts? Fresh walnuts are safe for dogs in small amounts. But black walnuts are toxic to dogs and moldy walnuts can contain mycotoxins that are poisonous. Whole walnuts are a canine choking hazard too. So are walnuts for dogs really worth the risk? Today we take a look at when walnuts can be safe for dogs, and when they’re dangerous, or even deadly. We’ll also look at the different types of walnuts like candied, seasoned or cooked walnuts, and some healthier walnut alternatives.


  • Can dogs eat walnuts?
  • Are walnuts dangerous or poisonous to dogs?
  • Can dogs eat walnuts whole or are they a choking hazard?
  • Should dogs eat candied walnuts?
  • Can dogs eat cooked walnuts?
  • Can dogs eat black walnuts?

Can Dogs Eat Walnuts?

Walnuts are actually considered stone fruits. You crack open their hard, wrinkled shells to get to the equally wrinkled yet edible nut inside. And for humans, walnuts have many nutritional benefits as a source of good fats, protein, fiber, and many other vitamins and minerals. Eating walnuts can help decrease cholesterol, heart, and neurological problems, help increase bone health and help address many other health issues including gallstones and epilepsy. But are walnuts for dogs okay? Or are walnuts poisonous to dogs?

Well, some nuts, such as cashew nuts, are okay for dogs in small quantities. But others, such as macadamia nuts, should never be ingested by dogs due to their toxicity. So where do walnuts fall on this spectrum? Do walnuts and dogs make a good combination? Are walnuts safe for dogs to eat?

The short answer is that most fresh walnuts (like the English variety) aren’t dangerous in small amounts, but black walnuts and moldy walnuts are very toxic. Plus, the larger size of walnuts and not preparing them properly can pose a hazard to your dog. Have you ever been concerned that your dog ate walnuts? Let’s take a look at why tiny amounts of English walnuts can be okay, but why we recommend avoiding them altogether.

Walnuts and Dogs

As previously mentioned, walnuts are often praised as a healthy choice for people, but this doesn’t automatically mean walnuts are just as healthy for dogs. Many articles and pet health websites suggest high-fat foods are bad for dogs, who have adapted to a diet with a high level of carbohydrates. However, recent studies have shown that fats and proteins naturally make up half of a dog’s optimum diet each, with carbohydrates only consisting of a tiny percentage. So, while dogs shouldn’t be allowed to gorge on lots of fats, having a good level of fats in their diet isn’t automatically unhealthy.

But, human treats like walnuts are not a very healthy addition to your dog’s diet over time. High calorie and fat content can lead to issues of obesity and also pancreatic concerns for your dog if they have a sensitive stomach or are prone to this disease.

When are Walnuts Bad For Dogs?

The most important thing to remember is that black walnuts and moldy walnuts are bad for your dog. But, even those that are not poisonous are hard and small. So, it’s easy for them to cause internal blockages. Let’s take a closer look at times when walnuts are dangerous to our dogs.

Are Walnuts Poisonous To Dogs?

If you wondering, “Are walnuts toxic to dogs?” The answer is yes, in a few instances, walnuts can be toxic to dogs. You have to be certain what kind of walnuts you’re feeding your dog. The two most common types of walnut are the black walnut and the English (Persian) walnut. The black walnut has a harder shell, which is why the English walnut was chosen for wider commercial production. While English walnuts are not toxic to dogs, research has shown that black walnuts are toxic to dogs.

Additionally, walnuts are susceptible to mold because of their high water content. So another big risk to dogs is moldy walnuts that contain tremorgenic mycotoxins. Tremorgenic mycotoxins are produced by fungi that can be fatal to dogs when ingested. They are a type of mycotoxin that causes muscular and neurological symptoms in dogs. So ingesting moldy walnuts can be really harmful to them.

Severe symptoms in dogs include vomiting, seizures, and tremors. So, what should you do if you notice these symptoms, or if you know that your dog has eaten moldy walnuts? Scroll down to the section on what to do if your dog eats moldy or black walnuts.

Can Dogs Eat Walnuts Whole?

Another concern is the size of walnuts. Walnuts are bigger than other nuts like peanuts. And the size of walnuts both shelled and unshelled can pose a choking hazard, especially for smaller dogs. And they can also possibly cause stomach problems for dogs as they are more difficult to digest and could cause bowel obstructions if they consume a lot of them. So what does this all mean?

Are Walnuts Safe for Dogs?

So if you’re wondering, “Are walnuts safe for dogs?” the general answer is not really. Some walnuts can be perfectly safe for dogs. But, if you have any concern about the freshness of a walnut, it’s best to avoid letting your dog try it. Plus, not offering this snack will avoid the risk of choking.

Are Walnuts Good For Dogs?

Again, the dangers of black walnuts or moldy walnuts far outweigh any small health benefits walnut may have as an occasional treat. So, no, walnuts are generally not good for dogs. Although fresh walnuts won’t necessarily harm your dog, there are plenty of better treats out there that you can share with your pet.

Can Dogs Eat Walnuts Candied or Seasoned?

Candied walnuts would also not be beneficial to your dog. In addition to the previously stated concerns, added sugar to your dog’s diet can lead to weight gain and obesity, and even teeth problems. And another concern would be artificial sweeteners in commercially-produced and store-bought candied walnuts that may contain Xylitol that is especially harmful to dogs. Plus, any walnuts that have added salts, seasonings, or chemicals can be harmful to your dog.

In general, sugar, salt, and flavorings can cause stomach upset to your dog and even worsen any underlying health conditions.

Can Dogs Eat Cooked Walnuts?

Some people may think that cooking unshelled English walnuts by boiling them or roasting them may help get rid of any mold in them. But that is not the case, because they are chemical by-products and are not bacterial organisms. The same rule for raw walnuts applies to cooked walnuts: fresh English walnuts in small quantities can be okay but black walnuts or moldy walnuts are problematic.

Can Dogs Eat Walnuts When They’re Black or Moldy?

If you’ve seen your dog eat black walnuts or moldy walnuts or thin they have, call your vet immediately or take them to an emergency clinic.

There are several symptoms you might start to see. Ingesting black walnuts can cause tremors, vomiting, or seizures. And tremorgenic mycotoxins in moldy walnuts can cause muscle tremors, seizures, panting, vomiting, weakness, increased heart rates and body temperatures, dehydration, and lack of appetite, amongst other symptoms. Studies of dogs with these symptoms have determined walnuts were the cause when their shells or remnants were found in the dog’s vomit. People whose dogs ate moldy walnuts did not realize their dogs had consumed them until the symptoms were visible.

If your dog has eaten black or moldy walnuts and is experiencing the symptoms listed above, the situation should be considered to be serious. If your dog has black walnut or mycotoxin poisoning, it will need to be hospitalized and treated as soon as possible.

Treatment for Black Walnut and Mycotoxin Poisoning

Your dog will most likely have its stomach pumped and given activated charcoal to absorb the toxins in your pup’s digestive system. If your dog is experiencing seizures, the treatment may be slightly different and could take slightly longer. It usually takes between one to two days for dogs to recover after treatment, but you should always watch out for any returning symptoms. If any symptoms return, make sure to inform your vet straight away. Some dogs can take longer to heal than others, even up to a week, so make sure to be on the lookout for any irregularities in your dog’s health.

For mycotoxin poisoning, many studies that have examined the effects of moldy walnuts on dogs have shown that they made a full recovery. However, this can depend on the amount ingested by the dog and how quickly it is realized so something can be done to help your pet. There are fewer studies on the effects of black walnuts on dogs and their recovery, but eating black walnuts appears to be less severe than eating black walnut tree wood.

Fresh English Walnuts are Safe in Small Quantities

Remember, fresh English walnuts are safe they aren’t moldy and therefore don’t have tremorgenic mycotoxins. So consuming a small amount of fresh English walnuts shouldn’t cause the symptoms listed above. However, if your dog gorges on a large amount of fresh English walnuts, the high-fat levels they ingest could cause vomiting, so you should call your vet for advice on how to proceed. They will know the best way to help, depending on how much your dog has ingested.

Should I Give My Dog Walnuts?

If you’re still wondering, “Are walnuts bad for dogs?” there are a few things to consider.

Because fresh English walnuts are safe for dogs in small quantities, you may think it’s okay to give English walnuts to your dog. But it may not be worth the risk. There are many other safer options you can choose to introduce new fats into your dog’s diet. Risking mycotoxin poisoning isn’t worth it for the few health benefits walnuts give your dog.

Your dog should never eat black walnuts or moldy walnuts because your pet can become really sick and can require emergency treatment. There are tons of other foods your dog can eat if you’re looking for something you can share with your dog as a snack.

How to Prepare Walnuts for Dogs

If you do give your dog some walnuts, they should be the fresh English variety and not have any mold. If you have walnuts still in their shells, don’t feed them as is. Crack them open and make sure there are no pieces of shell in the walnut. Don’t feed whole walnuts with their big shells or the sharp bits of cracked open shells. Both are choking hazards and could cause harm to your dog’s digestive system.

Finally, you should only serve English walnuts to your dog plain without any salt, sugar, or seasonings.

Alternatives to Walnuts for Dogs

  • Carrots
  • Peanuts
  • Pistachios

Can Dogs Eat Walnuts?

Fresh English walnuts can provide dogs with some healthy fats. But there are other safer alternatives to feed your dog. So, are walnuts bad for dogs? Overall, yes they are. Even gorging on English walnuts can cause sickness or stomach aches for many dogs due to the high-fat content.

Are walnuts poisonous to dogs? Yes, some are. Black walnuts or moldy walnuts can cause much more serious issues, such as seizures. If your dog ate black walnuts and moldy walnuts, you should seek immediate help and medical attention from your vet. There are plenty of other options to increase the fat content in your dog’s diet. Walnuts aren’t worth the risk they pose to your dog.

Do you have any experiences of when your dog ate walnuts? Do you know any good alternatives to walnuts for healthy fats? Let us know in the comments.

References and Further Reading

  • Boysen, S.R., et al., “Tremorgenic Mycotoxicosis in Four Dogs from a Single Household,” Journal of the American Veterinary Medical Association (2002).
  • Coleman, A.E. & Merola, V, “Clinical Signs Associated with Ingestion of Black Walnut Tree (Juglans Nigra) Wood, Nuts, and Hulls in Dogs: 93 Cases (2001–2012),” Journal of the American Veterinary Medical Association (2016).
  • Evans, T.J. & Gupta, R.C., “Tremorgenic Mycotoxins,” Veterinary Toxicology (2018).
  • Munday, J.S., et al., “Presumptive Tremorgenic Mycotoxicosis in a Dog in New Zealand, After Eating Mouldy Walnuts,” New Zealand Veterinary Journal (2011).
  • Murphy, L.A. & Coleman, A.E., “Xylitol toxicosis in dogs,” The Veterinary Clinics of North America, Small Animal Practice (2012).
  • Olsen, N, & Ware, M, ”What are the health benefits of walnuts?” Medical News Today
  • ”Poisons,” Pet Poison Helpline.
  • Poulose, S.M., et al., “Role of Walnuts in Maintaining Brain Health with Age,” The Journal of Nutrition (2014).
  • Richard, J.L., et al., “Moldy Walnut Toxicosis in a Dog, Caused by the Mycotoxin Penitrem A,” Mycopathologica, (1981).
  • Simopoulos, A.P., 2004, “Health Effects of Eating Walnuts,” Food Reviews International (2004).

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