Many food consumers may not be aware that there are a few types of cinnamon.  Among them, cassia cinnamon or Cinnamomum cassia contains a toxic chemical called coumarin, which is known to damage the liver.Cinnamomum cassia, also known as Chinese cassia or Chinese cinnamon, is a widely cultivated spice in Southern China and in southern and eastern Asia including India, Indonesia,  Laos, Malaysia, Taiwan, Vietnam, and Thailand.In the U.S. Chinese cassia is often sold under the name cinnamon.In comparison, true cinnamon or Ceylon cinnamon or Cinnamomum zeylanicum contains little coumarin. (David Liu)