Most Americans consider cinnamon a simple flavoring, but in traditional Chinese medicine, it's one of the oldest remedies, prescribed for everything from diarrhea and chills to influenza and parasitic worms. Cinnamon comes from the bark of a small Southeast Asian evergreen tree and is available as an oil, extract, or dried powder. It's closely related to cassia ( C. cassia) and contains many of the same components, but the bark and oils from C. zeyleanicum are thought to have a better flavor.

Based on the results of one preliminary double-blind, placebo-controlled study, cinnamon has been widely advertised as an effective treatment for type 2 diabetes as well as high cholesterol. However, the evidence for this is mixed.

Germany's Commission E approves cinnamon for improving appetite and relieving indigestion; however, these uses are not backed by reliable scientific evidence.1

Two animal studies weakly suggest that an extract of cinnamon bark taken orally may help prevent stomach ulcers.2,3

Preliminary results from test tube and animal studies suggest that cinnamon oil and cinnamon extract have antifungal, antibacterial, and antiparasitic properties.4-10 For example, cinnamon has been found to be active against Candida albicans, the fungus responsible for vaginalyeast infections and thrush (oral yeast infection), Helicobacter pylori (the bacteria that causes stomach ulcers), and even head lice. However, it's a long way from studies of this type to actual proof of effectiveness. Until cinnamon is tested in double-blind human trials, we can't conclude that it can successfully treat these or any other infections. (For why double-blind studies are so important, see Why Does This Database Rely on Double-blind Studies?)