Since I've been posting a lot about the benefits of cinnamon lately I think it is also important to mention that many people have an allergy to cinnamon.
There's a great discussion about cinnamon allergy on Metafilter.
I also found some useful information about cinnamon allergy on one site:
Cinnamon oil has been known as a contact allergen since the 19th century, when sucking on Cinnamon-soaked toothpicks was found to cause contact dermatitis ... The most common reactions described are those of allergic contact dermatitis or irritant contact dermatitis ... Although immediate hypersensitivity reactions are possible, many reported allergic contact dermatitis cases occur as a result of delayed type IV reactions. (Phadia)
Because many products contain cassia and not true cinnamon, it may be difficult to figure out which one you are allergic to. Most "cinnamon" on grocery store shelves is actually cassia. If you have an unidentified allergy that occurs when you eat foods that contain generic "spices" or cinnamon, you might want to investigate the possibility of a cinnamon allergy.
If you know that it's cassia that you're allergic to, check out our list of the best true Ceylon cinnamon powders to make sure you're getting the right kind: 4 Best Cinnamon Powders
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