🚫 Black walnut toxicity in dogs 🌰 Did you know that black walnuts can actually be harmful to dogs?? The hulls and any moldy nuts can cause stomach upset, tremors, and weakness. If they eat moldy ones, it can even affect their nervous system. Dogs can also have a reaction if they’re exposed to black walnut wood shavings, which are sometimes used in horse bedding, and may show signs of lameness or seem very tired. If your dog eats black walnuts or starts showing sudden weakness or tremors, call