The quick answer: No, dogs should not eat nutmeg because it is toxic to dogs.
Though the amount of nutmeg baked into a pastry is typically not enough to cause serious implications, this spice is toxic to dogs in large quantities.
Often finely ground and used as a spice, nutmeg is the hard seed of a dark-leaved evergreen tree called Myristica fragrans. Nutmeg is toxic due to a compound called myristicin which, when consumed in large quantities, is toxic to both pets and people.
A pet would need to ingest a significant amount of nutmeg to experience toxicity. Nutmeg is a hallucinogenic, so consuming a large amount of it can be a frightening experience for your dog or cat. Too much nutmeg can also cause symptoms like disorientation, increased heart rate, dehydration, high blood pressure, and seizures. If your pet has gotten into your spice collection and consumed a considerable amount of nutmeg, be sure to contact your veterinarian or the Pet Poison Helpline.
If your dog ate a baked treat that contains nutmeg, it is unlikely to cause toxicity, though it could cause mild stomach upset, vomiting, or diarrhea. Regardless, baked goods should be kept well out of reach because they could contain ingredients that are toxic to dogs. Such ingredients that are highly toxic to dogs include raisins, chocolate, macadamia nuts, onion powder, and xylitol. Other ingredients like sugar, salt and butter can also cause tummy troubles for your dog. The best way to keep your pup safe and healthy is to avoid sharing baked goods with them and educating your guests on the matter as well.
While on the subject of spices, you may also be wondering whether or not cinnamon is toxic to dogs. Find out if dogs can eat cinnamon.