Cassia cinnamon is a plant. People use the bark and flower for medicine. Cassia cinnamon is used for many conditions, but so far science has not confirmed that it is effective for any of them. Research does show, however, that it is probably not effective for lowering blood sugar in type 1 or type 2 diabetes.In addition to diabetes, Cassia cinnamon is used for gas (flatulence), muscle and stomach spasms, preventing nausea and vomiting, diarrhea, infections, the common cold, and loss of appetite.assia cinnamon is used for many conditions, but so far science has not confirmed that it is effective for any of them. Research does show, however, that it is probably not effective for lowering blood sugar in type 1 or type 2 diabetes.