Cinnamon contains a chemical called coumarin, which is used for making rat poison. Coumarin is also found in other plants such as sweet woodruff, sweet grass, sweet-clover, and tonka bean. Cinnamon flavor is generally cassia bark steam-distilled to concentrate the cinnamaldehyde, for example, to about 93% . European health agencies have warned against consuming high amounts of cassia bark, one of the four main species of cinnamon, because of its coumarin content. According to the German Federal Institute for Risk Assessment (BFR), 1 kg of (cassia) cinnamon powder contains about 2.1 to 4.4 g of coumarin. Powdered cassia cinnamon weighs 0.56 g/cm3, so a kilogram of cassia cinnamon powder equals 362.29 teaspoons. One teaspoon of cassia cinnamon powder therefore contains 5.8 to 12.1 mg of coumarin, which may be above the tolerable daily intake.
A Reddit post warns that if you smell cinnamon in your drink, do not drink it, as it may be poisoned. A recent article on Verywell Health discusses a TikToker who claims to have been poisoned by cinnamon. A YouTube video also warns that if your beverage smells like cinnamon, you should toss it. It is important to note that while coumarin can be toxic in high doses, the amount found in normal consumption of cinnamon is generally considered safe.
