A very enlightening article, though the distinction between the two main cinnamon varieties coumarin content. The common cinnamon, cassia, from China and Indonesia, found in supermarkets, has a much higher coumarin content. Ceylon cinnamon from Sri Lanka, Madagascar and Seychelles, also known as "true" cinnamon, contains up to sixty-per-cent less coumarin in powdered form and eighteen time less in stick form. Therefore reducing the negative effect on the liver and as always moderation is key.