
Cinnamon (Cinnamomum verum)
Photo: Simon A. Eugster · CC BY-SA 3.0
- Circulatory
- 4 conditions
- Licensed photo
Overview
Cinnamon (Cinnamomum verum or C. zeylanicum) is a small evergreen tree, prized for its fragrant, sweet-spicy bark. Cinnamon has a long history of use in traditional medicine in China, India and Persia, where it was thought to help inflammation, nerve pain, heart disease and cough (NCCIH). NCCIH says research doesn't clearly support cinnamon for any health condition, and it is unclear whether it helps diabetes.
Traditional uses & properties
Blood Sugar: Promoted today for diabetes; NCCIH says it is unclear whether cinnamon helps diabetes.
Safety & precautions
Essential Oil: Highly concentrated, can be toxic, and is not advisable for internal use. Pregnancy & Breastfeeding: Cinnamon bark and oil (beyond normal food amounts) are generally avoided. Excess Doses: NCCIH notes that larger amounts or long-term use of cinnamon are sometimes linked to gastrointestinal problems or allergic reactions, and large amounts may lower blood sugar excessively. Allergy: Occasionally causes allergic reactions.
Educational reference only - not medical advice. Herbs can interact with medications. Consult a qualified healthcare provider before use. Full disclaimer.
Drug interactions
Concerns center on coumarin, which some cassia cinnamon products contain in high amounts, and on enzyme effects seen in the laboratory. NCCIH cautions that people with liver disease may be more vulnerable if they use cassia for long periods, and LiverTox describes rare reports of liver injury linked to cinnamon. [1, 2, 3]
- Statins
- MSK cites reports of hepatitis in people who took cinnamon together with a statin. [2]
- Cancer medicines and nicotine
- NCCIH says research it partly funded offers theoretical grounds for thinking some cinnamon components may interact with an anticancer drug or with nicotine. [1]
- Pioglitazone and other diabetes medicines
- In animal studies cinnamon increased how much pioglitazone was absorbed. MSK also notes cinnamon may lower blood glucose, though the evidence is mixed. [2]
- Medicines broken down by liver enzymes
- Preclinical studies suggest cinnamon inhibits several CYP enzymes (2C9, 3A4, 2A6 and 2D). Relevance in people is undetermined. [2]
How to read this section: each entry is HerbMate's summary of what the cited sources report. Words such as "may", "theoretical" or "in laboratory or animal studies" mean the effect has not been confirmed in people, and "case report" means it was seen in one or a few patients. A medicine that is not listed here has not been shown to be safe with this herb. The numbers in brackets link to the sources at the foot of the page.
Habitat
Native to India and Sri Lanka, cinnamon trees grow in tropical forests up to about 1,600 ft (500 m) in elevation. Commercially, they are heavily cultivated in regions like the Philippines and the Caribbean. The bark is harvested by cutting back young trees, stripping the outer bark, and drying the inner layer into characteristic quills.
Sources
The interaction notes and the statements on this page that name a source were written by HerbMate from these references, which were last checked in October 2026. They are summaries, not medical advice; ask a pharmacist about your own medicines.
Traditionally used for
- Poor Circulation4 herbs · 2 free
- Indigestion24 herbs · 2 free
- Diabetes11 herbs · 2 free
- Cold and Flu16 herbs · 2 free
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Frequently asked questions
What is Cinnamon (Cinnamomum verum) traditionally used for?
Traditional sources describe Cinnamon (Cinnamomum verum) as follows: Blood Sugar: Promoted today for diabetes; NCCIH says it is unclear whether cinnamon helps diabetes.
What safety cautions apply to Cinnamon (Cinnamomum verum)?
Essential Oil: Highly concentrated, can be toxic, and is not advisable for internal use. Pregnancy & Breastfeeding: Cinnamon bark and oil (beyond normal food amounts) are generally avoided. Excess Doses: NCCIH notes that larger amounts or long-term use of cinnamon are sometimes linked to gastrointestinal problems or allergic reactions, and large amounts may lower blood sugar excessively. Allergy: Occasionally causes allergic reactions.







