Yes Cassia in small amounts only, very quickly is toxic to the liver.

Ceylon is not toxic, and can and should be taken daily, a Tbsp is quite a lot, a tsp is sufficient to get the desired effect.

The preventative of cinnamon to Alzheimers is quite astonishing, I take daily for years now, Ceylon, no adverse issues.

[link to www.alzheimers.net (secure)]