What is the Toxicity of Cinnamon, and How Does It Affect Your Health?

January 8, 2026 •

4 min read

According to the European Food Safety Authority (EFSA), a key compound in common Cassia cinnamon, called coumarin, can cause liver damage when consumed in high doses over prolonged periods. Understanding the specific risks is crucial, as the toxicity of cinnamon depends heavily on the variety you are using.

Quick Summary

The toxicity of cinnamon is primarily linked to coumarin, a liver-damaging compound found in high concentrations in Cassia cinnamon, the most common type. Ceylon cinnamon contains minimal coumarin and is safer for regular use. Excessive intake can cause liver issues, mouth sores, allergic reactions, and may interfere with certain medications.

Key Points

Cassia vs. Ceylon: The primary toxicity of cinnamon comes from coumarin, which is found in high levels in Cassia cinnamon but only in trace amounts in Ceylon or "true" cinnamon.
Liver Damage: Excessive and prolonged consumption of high-coumarin Cassia cinnamon can cause hepatotoxicity, leading to liver inflammation and damage.
Daily Intake Limits: European health guidelines suggest a tolerable daily coumarin intake limit, which is easily exceeded with just one teaspoon of some Cassia products.
Drug Interactions: High doses of Cassia cinnamon can interfere with blood-thinning medications, diabetes drugs, and other medications that impact liver function.
Allergic Reactions and Sensitivities: Compounds in cinnamon like cinnamaldehyde can cause allergic reactions, including mouth sores, skin irritation, and breathing problems in sensitive individuals.
Safe Consumption: For daily use, opt for Ceylon cinnamon. For Cassia, moderate intake is key, and sensitive individuals should be particularly cautious.

Cinnamon is a popular spice used worldwide, but its safety profile depends on the type. While occasional, moderate consumption is generally safe, excessive intake, particularly of the more common and cheaper Cassia variety, can lead to serious health issues. The primary concern is the presence of a compound called coumarin, which is known to be hepatotoxic, meaning it can damage the liver.

The Difference Between Cassia and Ceylon Cinnamon

Not all cinnamon is created equal. The two main varieties, Cassia and Ceylon, have significantly different chemical compositions, with coumarin content being the most critical distinction for health. Cassia is the dominant cinnamon in the market due to its lower cost and more potent flavor, but this potency comes with a higher risk.

Cassia Cinnamon (Cinnamomum cassia)

Coumarin Content: Contains high levels of coumarin, which can range from 0.1% to 1.2% by weight. For a sensitive individual or a person with existing liver conditions, consuming too much Cassia can be harmful.
Flavor: Characterized by a strong, spicy, and often pungent flavor.
Appearance: Hard, reddish-brown bark that rolls into a single thick layer.

Ceylon Cinnamon (Cinnamomum verum)

Coumarin Content: Contains only trace amounts of coumarin (0.004% to 0.1%). This makes it significantly safer for regular and high-volume consumption, especially in supplements or daily tea.
Flavor: Milder, sweeter, and more aromatic with subtle citrus notes.
Appearance: Thin, delicate, multi-layered, and brittle quills that are easy to grind.

Potential Health Risks of Excessive Cinnamon Consumption

While the primary toxicological concern revolves around coumarin and liver health, other side effects and potential risks are associated with high cinnamon intake, especially with the Cassia variety.

Liver Damage: High levels of coumarin, especially from Cassia cinnamon, can lead to hepatotoxicity over time. Symptoms of liver damage can include abdominal pain, fatigue, nausea, and jaundice.
Mouth Sores: Some individuals are sensitive to cinnamaldehyde, a compound in cinnamon, which can cause allergic reactions like mouth sores, also known as cinnamon stomatitis.
Low Blood Sugar: Cinnamon is known for its blood sugar-lowering effects, which can be beneficial for some. However, for people with diabetes taking medication, excessive cinnamon can cause blood sugar levels to drop too low (hypoglycemia).
Medication Interactions: The anticoagulant properties of coumarin in Cassia can interact negatively with blood-thinning medications like warfarin, increasing the risk of bleeding. It can also interfere with medications for liver disease and diabetes.
Breathing Problems: Attempting to swallow large amounts of dry cinnamon, such as with the dangerous "cinnamon challenge," can cause respiratory issues. The fibrous spice is not easily broken down in the lungs and can lead to lung inflammation or aspiration pneumonia.
Allergic Reactions: Beyond mouth sores, systemic allergic reactions to cinnamon can occur, though they are rare. Symptoms include skin rashes, hives, swelling, and difficulty breathing.

Comparison Table: Cassia vs. Ceylon Cinnamon


Feature	Cassia Cinnamon	Ceylon Cinnamon
Primary Growing Region	China, Indonesia, Vietnam	Sri Lanka (formerly Ceylon)
Coumarin Content	High	Very Low (Trace Amounts)
Health Concern	High coumarin poses risk of liver damage with regular intake	Safe for regular, long-term consumption
Flavor Profile	Strong, intense, and spicy	Mild, sweet, and delicate
Appearance	Thick, hard, single-rolled bark	Thin, multi-layered, and brittle quills
Price	Typically cheaper and more widely available	More expensive and less common

Recommended Intake and Safety Tips

To safely enjoy cinnamon's health benefits, a few guidelines should be followed. For most people, consuming cinnamon in typical culinary amounts is not a cause for concern. The risk increases with regular, high-volume consumption, particularly from supplements.

Choose Ceylon for Regular Use: If you add cinnamon to your food or tea daily, or take supplements, opt for Ceylon cinnamon to avoid the coumarin risk.
Limit Cassia Intake: For most adults, health authorities suggest limiting Cassia cinnamon to about half a teaspoon daily to stay within safe coumarin limits.
Be Mindful of Children: The coumarin limit is based on body weight, so children are at a higher risk of exceeding safe levels with smaller amounts of Cassia.
Consult a Healthcare Provider: If you have a liver condition, diabetes, or take any medication that affects the liver or blood clotting, it is essential to speak with a healthcare provider before increasing your cinnamon intake or taking supplements.
Read Product Labels: Check labels for the type of cinnamon. If a product just says "cinnamon" without specifying, it is likely the higher-coumarin Cassia variety.

Conclusion

The toxicity of cinnamon is not a simple yes or no answer; it is nuanced and depends on the variety and quantity consumed. For the vast majority of people who use cinnamon as a flavor enhancer in small amounts, there is minimal risk. However, individuals who consume cinnamon regularly in larger quantities, especially through supplements, should be vigilant about the type of cinnamon they choose. Prioritizing Ceylon cinnamon, the “true cinnamon,” for daily use is the safest way to enjoy its potential health benefits without the risk of coumarin-induced liver toxicity. By understanding the difference between Cassia and Ceylon and adhering to sensible consumption limits, you can savor this versatile spice without worry.

Learn more about coumarin and its effects from the German Federal Institute for Risk Assessment.

Frequently Asked Questions

The toxicity risk in cinnamon is primarily associated with the Cassia variety, which contains high levels of the coumarin compound. Ceylon cinnamon contains only trace amounts of coumarin and is considered much safer for regular consumption.

The amount of cinnamon that becomes toxic depends on the type. For high-coumarin Cassia cinnamon, consuming more than about half a teaspoon daily can risk exceeding safe coumarin limits for many adults. In contrast, Ceylon cinnamon is safe at much higher intake levels.

Symptoms of coumarin-induced liver damage can include fatigue, nausea, abdominal discomfort, and jaundice (yellowing of the skin and eyes). These symptoms indicate that the liver is under stress and require medical attention.

No, Cassia cinnamon is not inherently unsafe for everyone. It can be safely enjoyed in moderation for culinary purposes. The risks arise from high and regular intake, particularly in supplements, or for individuals with pre-existing liver conditions.

Children are more vulnerable to coumarin toxicity due to their smaller body weight. It is best to use Ceylon cinnamon for any children’s dishes and to be very conservative with Cassia, as even small amounts can exceed their safe daily coumarin limit.

Yes, the "cinnamon challenge," which involves swallowing a spoonful of dry cinnamon, is very dangerous. The dry, fibrous spice can be easily inhaled into the lungs, causing breathing problems, lung inflammation, and even aspiration pneumonia.

On the label, look for "Ceylon" or the scientific name Cinnamomum verum. If the label only says "cinnamon," it is likely the high-coumarin Cassia variety. Physically, Ceylon sticks are thin, multi-layered, and brittle, while Cassia sticks are thick, hard, and single-rolled.