Cassia cinnamon is the problem one because it contains a significant amount of coumarin so that anyone taking blood thinners like Warfarin should not use a lot of cassia cinnamon.
Ceylon (or True) Cinnamon OTOH, has a negligible amount of coumarin so it is safe to use in such cases. Ceylon cinnamon also has a slightly sweeter taste than cassia cinnamon.
OK — HTH
Paul M.
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