Ceylon cinnamon can possibly lower blood sugar in people with Type 2 diabetes, and can also interfere with blood sugar levels after surgery, explains WebMD. Diabetics should watch for signs of hypoglycemia and track blood sugar levels carefully if using cinnamon bark. Individuals should abstain from using cinnamon bark two weeks prior to surgery.
Consuming cinnamon oil orally is a risk, notes WebMD. Doing so can aggravate the skin and mucous membranes, including the urinary tract, stomach and intestines, leading to drowsiness, diarrhea, vomiting and dizziness.
Eating large amounts of Ceylon cinnamon is possibly unsafe, while the amount contained in food and medicine is likely safe, states WebMD. Given the lack of information about taking cinnamon bark while pregnant or breast-feeding, doctors recommend only consuming it in foods and avoiding copious amounts. Anti-diabetes drugs such as Glucotrol, Avandia, Amaryl and Orinase may need to be adjusted if taking Ceylon cinnamon due to the potential for blood sugar going too low.
Cinnamon bark may be an effective treatment for premature ejaculation when put in a special cream combined with other ingredients, according to WebMD. While there are claims of cinnamon's effectiveness in treating other conditions, including hay fever, food poisoning, irritable bowel syndrome and yeast infections, there is insufficient evidence to confirm this.