Why?
Cinnamon is not toxic to dogs in very small amounts but it can irritate the mouth, skin, and digestive system. It can cause low blood sugar and liver disease in large amounts.
How much can dogs have?
Very small amounts in cooked food (like a dog biscuit recipe) are not harmful. Avoid intentionally feeding it.
What to watch out for
Cinnamon powder can irritate lungs if inhaled. Cinnamon oils are much more concentrated and more dangerous. Essential oil versions should never contact dogs.