Can my dog eat Macadamia nuts? Macadamia nuts are toxic to dogs, even in cookies, and even if the dog says it’s okay. Macadamia nuts are common in cookies, muffins, trail mix, and even cereal bars. They are perfectly safe for humans to eat and cats don’t seem to react to them, but even small amounts can be very dangerous to dogs. Symptoms of Macadamia Nut Poisoning include: Hind leg weakness Lethargy Fever Tremors Diarrhea Vomiting Call your veterinarian. Depending on your dog’s size, how much was ingested, symptoms, and if the nuts were eaten together with something else that’s toxic to dogs, your vet might ask you to come in, or give instructions on home care.