Coumarin in Cinnamon (IMAGE) American Chemical Society Caption Cinnamon obtained from the bark of Cassia trees (left) contains widely varying amounts of coumarin, a potential liver toxin, even among samples taken from a single tree. Credit American Chemical Society Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.