Can Dogs Eat Walnuts?
No. Walnuts aren't recommended: old ones or those fallen from the tree can carry molds with toxins that cause tremors and seizures, and they're also very fatty and can cause a blockage.
Why it's dangerous
The common (English) walnut isn't toxic in itself the way macadamia nuts are, but it spoils easily. Old, damp or fallen walnuts can carry molds (such as Penicillium) that produce tremorgenic mycotoxins, like penitrem A. In dogs they cause tremors, loss of coordination and seizures that can appear within a few hours, and the mold isn't always visible to the naked eye.
They also have about 65 g of fat per 100 g, so eating several can cause vomiting, diarrhea or pancreatitis. In the shell, or in large pieces, they can get stuck in the intestine or break a tooth. The black walnut, native to North America, is more toxic than the common walnut sold for eating. If you have a walnut tree in your yard, pick up the fallen nuts.
Is any amount safe?
There's no recommended amount. You can't see the mold risk with the naked eye, and the fat and shells aren't worth it either: not as treats and not in recipes.
Risks
- Tremorgenic mycotoxins in old or moldy walnuts
- High fat: diarrhea and pancreatitis
- Shells: blockage and broken teeth
- Fallen walnuts in the yard, especially black walnuts
- Baked goods, bread and treats with walnuts
Frequently asked questions
What happens if my dog eats a walnut?
If it's a fresh walnut in good condition, most likely nothing will happen in a medium or large dog. If it was old, moldy or picked up off the ground, or if your dog ate several or ate them in the shell, call your vet. Tremors from mycotoxins can appear within a few hours and need prompt treatment.
Are walnuts toxic to dogs like macadamia nuts?
Not in the same way. Macadamia nuts are toxic in themselves, while common walnuts become dangerous mainly when they're moldy. But since it's hard to tell whether a walnut has mold, and they're also very fatty and can get stuck, we don't recommend them under any circumstances.
General information reviewed against veterinary sources. If your dog has eaten something that worries you, call your vet or a 24-hour emergency vet right away, without waiting for symptoms.