Cassia cinnamon is likely safe when used in amounts commonly found in foods and when taken by mouth in medicinal doses.
Cassia cinnamon is possibly unsafe when taken by mouth in large amounts for a long period of time. Taking large amounts of cassia cinnamon might cause side effects in some people. Cassia cinnamon can contain large amounts of a chemical called coumarin. In people who are sensitive, coumarin might cause or worsen liverdisease. When applied to the skin, cassia cinnamon can sometimes cause skin irritation and allergic skin reactions.
Special Precautions & Warnings:
Pregnancy and breast-feeding: Not enough is known about the use of cassia cinnamon during pregnancy and breast-feeding. Stay on the safe side and avoid use.
Diabetes: Cassia cinnamon can lower blood sugar levels in people with diabetes. Watch for signs of low blood sugar (hypoglycemia) and monitor your blood sugar carefully, if you have diabetes and use cassia cinnamon in amounts larger than the amounts normally found in food.
Liver disease: Cassia cinnamon contains some chemicals that might harm the liver. If you have liver disease, do not take cassia cinnamon in amounts larger than the amounts normally found in food.
Surgery: Cassia cinnamon might lower blood sugar and might interfere with blood sugar control during and after surgery. Stop taking cassia cinnamon at least 2 weeks prior to a scheduled surgery.