Cinnamaldehyde and cinnamon oil vapors are extremely potent antifungal compounds. 3 Antibacterial actions have been demonstrated for cinnamon. The diterpenes in the volatile oil have also shown antiallergic activity. 5 Water extracts may help reduce ulcers. No more than a few drops of essential oil should be used and never for extended periods of time.
Some individuals develop allergies and dermatitis after exposure to cinnamon.
Therefore, only small amounts should be used initially in persons who have not previously had contact with cinnamon, and anyone with a known allergy should avoid it. Chronic use may cause inflammation in the mouth. The concentrated oil is more likely to cause problems. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Foods,Drugs, and Cosmetics, 2d ed. Cinnamon bark oil, a potent fungitoxicant against fungi causing respiratory tract mycoses.