Herb library · Herb · Cinnamomum verum (Ceylon), Cinnamomum aromaticum (cassia)
Cinnamon
The familiar spice, from the dried bark of Cinnamomum trees, sold as a supplement for blood sugar and weight loss. Research does not clearly support it for any health condition, and cassia, the common kind, can carry enough coumarin to matter in large amounts.
Traditional use
The bark, leaves, flowers, fruits and roots have a long history in traditional medicine and cooking in China, India, Persia and elsewhere, where cinnamon was thought to help with inflammation, nerve pain, heart disease and cough. Ceylon ("true") cinnamon grows mainly in Sri Lanka; cassia, from southeastern Asia, is the kind most sold in North America. Today it is promoted for diabetes and weight loss, Ceylon cinnamon for hay fever, and cassia on the skin as a mosquito repellent.
Traditional energetics
Galenic (hot or cold, dry or moist)
Hot and dry in the second degree. Culpeper's Complete Herbal (1814), p. 227 (opens in a new tab)
What studies show
- Insufficient
Diabetes and weight loss: there have been many studies, especially for diabetes, but it is unclear whether cinnamon helps; results are hard to interpret because it is often unclear which species or plant part was tested.
- Limited
Hay fever: preliminary research suggests a nasal spray with Ceylon cinnamon extract might improve symptoms.
- Insufficient
Mosquito repellent: it is unclear whether cassia works.
Be careful of
Cautions
- NoteLikely safe in the amounts used in food. Larger amounts or long use are sometimes linked to stomach problems or allergic reactions.
- AmountNever swallow a spoonful of cinnamon powder (the "cinnamon challenge" dare): serious harm is possible.
- ConditionCassia contains coumarin, which has been linked to liver effects. Food amounts usually contain too little to matter, but some cassia products are high in coumarin, and long use could be a problem for sensitive people, such as those with liver disease. Labels often do not say which species or plant part is inside.
- AllergySome cinnamon oils or powders can irritate the skin or cause contact dermatitis.
- InteractionThere are theoretical reasons to suspect some components may interact with an anticancer medicine or with nicotine.
- PregnancyFood amounts appear safe in pregnancy, but larger amounts of Ceylon cinnamon during pregnancy are considered unsafe. Little is known about larger amounts while breastfeeding.
- Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.
From the old books
What herbals and dispensaries of the past printed. History, in their words.
“with an odor similar to that of cinnamon, but not so strong or agreeable, and a corresponding taste more acrid, burning, and lasting, and at the same time mucilaginous. It is used in tinctures instead of cinnamon, and is the kind usually sold as cinnamon.”
“Cinnamon is often adulterated with the poorer sorts, and likewise with the bark after having been deprived of its oil.”
In scripture
Where the Bible names this plant, and which plant scholars think is meant.
I have perfumed my bed with myrrh, aloes, and cinnamon.
Cinnamon, which Tristram (1898) identifies as the bark of Cinnamomum zeylanicum (now C. verum), one of the two spices on this page; it did not grow in Syria and was brought from Ceylon. H. B. Tristram, The Natural History of the Bible (1898), pp. 346–347 (opens in a new tab)
“Also take fine spices: of liquid myrrh, five hundred shekels; and of fragrant cinnamon half as much, even two hundred and fifty; and of fragrant cane, two hundred and fifty; and of cassia five hundred, according to the shekel of the sanctuary; and a hin of olive oil.
Both spices on this page appear here. Tristram (1898) identifies the cassia of verse 24 (Hebrew kiddah) as Cinnamomum cassia, an import from the East, coarser than the cinnamon of verse 23. H. B. Tristram, The Natural History of the Bible (1898), pp. 340–341 (opens in a new tab)
Sources
- Cinnamon: Usefulness and Safety (opens in a new tab) · NCCIH · read September 25, 2026
Reviewed September 25, 2026.