The short answer: It is not recommended.
The long answer: Cinnamon is a dark red spice that is known for its strong scent and sweet flavour. According to the American Society for the Prevention of Cruelty to Animals (ASPCA), it is non-toxic to dogs, but since it presents no beneficial nutritional value for your pet, there is no need to add it to his diet.
Some dog owners occasionally sprinkle cinnamon powder over their pet’s meal to make it smell and taste more appetizing, but it isn’t something that you should do regularly. When cinnamon powder is inhaled incorrectly, it might cause your dog to gag, choke, cough, or experience difficulty in breathing. Too much cinnamon may create mouth, throat, and/or lung irritation, sensitization, as well as gastrointestinal upset.
What to do if your dog accidentally eats cinnamon: Observe how your dog reacts to the cinnamon he ate. More than one teaspoon of cinnamon powder in a short period of time can lead to vomiting, diarrhea, indigestion, low blood sugar, changes in heart rate, and liver disease.
In summary: Keep your dog away from cinnamon powder, cinnamon sticks, ground cinnamon, cinnamon essential oils, or even baked goods with cinnamon in them. Though cinnamon isn’t lethal for dogs, you’re better off not exposing him to this aromatic spice. Instead of cinnamon, discover which ingredients dogs can safely eat in our “can dogs eat” category.