Cinnamon contains a number of compounds in addition to cinnamaldehyde. Beta-Caryophyllene is responsible for the spiciness of cinnamon, while linalool provides its spicy but flowery scent. Other compounds, such as eugenol, anethole and cinnamyl acetate, also have a direct influence on cinnamon's distinctive smell and flavor. Some of these compounds can be found in only a few other plant species, including clove, hemp and nutmeg.
Cinnamon is also believed to be rich in antioxidants, which fight the free radicals that can damage cells and potentially lead to conditions such as heart disease, cancer and premature aging [source: MedlinePlus]. Additionally, proponents claim that cinnamon also has antimicrobial, antiseptic, antifungal, antibiotic, stimulant and astringent properties [source: Cosmetics and Toiletries]. These properties may make it effective in treating certain infections, and some believe it can even improve cognitive processing [source: Food Navigator].
However, cinnamon also contains a component called coumarin, which can potentially be toxic to the kidneys and liver when consumed in excess. The German Federal Institute for Risk Assessment has warned that daily consumption of more than 0.1 milligram of coumarin per kilogram of body weight can be dangerous. Consuming cinnamon in excess can also cause nausea, vomiting, redness of the face and lip swelling, and burning in the lungs and chest, if inhaled. Coumarin may have anti-clotting properties, too, so people on blood thinner medications should use cinnamon with caution [source: Davidson].
Read on to learn how cinnamon was used by different cultures throughout history.