Who cannot consume cinnamon? A guide to safe cinnamon consumption

November 1, 2025 •

4 min read

While beloved worldwide, a study found Cassia cinnamon can contain up to 63 times more coumarin than Ceylon. This critical difference is why knowing who cannot consume cinnamon or should moderate their intake is essential for certain individuals.

Quick Summary

Certain individuals with liver conditions, bleeding disorders, or specific allergies should avoid or limit cinnamon intake. This is especially important for those taking certain medications, pregnant or breastfeeding women, and those consuming large amounts of Cassia cinnamon due to high coumarin levels.

Key Points

High Coumarin Risk: Regular, high-dose consumption of Cassia cinnamon can cause liver damage, especially in those with pre-existing conditions.
Ceylon is Safer: For daily or therapeutic use, choose Ceylon (true) cinnamon due to its minimal coumarin content.
Medication Interactions: Cinnamon can interfere with blood thinners, diabetes drugs, and certain liver-metabolized medications.
Allergy Alert: Individuals allergic to cinnamaldehyde should avoid cinnamon to prevent symptoms ranging from mouth sores to anaphylaxis.
Limit During Pregnancy: High doses from supplements are not recommended for pregnant or breastfeeding women; small amounts in food are generally safe.
Know Your Spice: Always check labels, as most common store-bought cinnamon is Cassia, with its higher coumarin level.

Understanding the two main types of cinnamon

Not all cinnamon is created equal. The two primary types available in the market are Cassia and Ceylon, and their differing chemical compositions are key to understanding their safety profiles.

Cassia cinnamon, which is the most common and inexpensive variety sold in North America, is sourced from the Cinnamomum cassia tree. It contains a high concentration of coumarin, a natural flavoring that can be toxic to the liver in large doses. Ceylon cinnamon, often called “true cinnamon” and originating primarily from Sri Lanka, comes from the Cinnamomum verum tree. It contains only trace amounts of coumarin, making it the safer option for frequent and high-dose consumption. This distinction is crucial for sensitive individuals or those who use cinnamon therapeutically, as the risks associated with excessive Cassia intake do not apply equally to Ceylon.

Who should approach cinnamon with caution

For certain groups, the risks of cinnamon consumption, especially Cassia cinnamon, outweigh the benefits. Consultation with a healthcare provider is essential for anyone in these categories.

Individuals with Liver Disease: The high coumarin content in Cassia cinnamon poses a significant risk for those with pre-existing liver conditions, such as hepatitis or fatty liver disease. Long-term, high-dose exposure to coumarin can cause or worsen liver toxicity.
Those on Blood-Thinning Medication: Coumarin has natural anticoagulant properties. For individuals taking blood thinners like warfarin, excessive intake of Cassia cinnamon can heighten the risk of bleeding by interacting with the medication.
Diabetics taking Blood Sugar Medication: Cinnamon can lower blood glucose levels. When combined with prescription diabetes medication, such as insulin or metformin, large amounts of cinnamon (particularly in supplement form) could cause blood sugar to drop dangerously low, a condition called hypoglycemia.
People with a known Cinnamon Allergy: Allergies to cinnamon, though relatively uncommon, can trigger reactions in sensitive individuals. The compound cinnamaldehyde is often the culprit and can cause symptoms ranging from mouth sores (contact stomatitis) and skin rashes to more severe reactions like swelling and anaphylaxis.
Pregnant and Breastfeeding Women: Medical experts recommend that pregnant and nursing individuals avoid cinnamon supplements and large quantities of the spice. While small amounts used in cooking are generally considered safe, there is a lack of sufficient research on the effects of high-dose consumption on fetuses and infants. High doses may also carry a theoretical risk of triggering uterine contractions.

The risks of excessive consumption

Even in healthy individuals, overconsumption of cinnamon can lead to unwanted side effects.

Mouth Sores: The compound cinnamaldehyde can cause oral irritation, leading to painful mouth sores or swelling of the lips and tongue in some people.
Gastrointestinal Issues: Taking too much cinnamon can irritate the gastrointestinal tract, causing stomach upset, nausea, or diarrhea.
Breathing Problems: Ingesting a large quantity of dry, ground cinnamon powder, famously seen in the unsafe 'cinnamon challenge,' can lead to breathing difficulties. The fine fibers can be inhaled into the lungs, potentially causing inflammation and scarring.

Comparison of Cassia vs. Ceylon Cinnamon


Feature	Cassia Cinnamon	Ceylon Cinnamon (True Cinnamon)
Origin	Mainly China, Indonesia, and Vietnam	Primarily Sri Lanka and Southern India
Coumarin Content	High	Very Low (Trace Amounts)
Appearance	Thick, reddish-brown bark that forms a single, hard roll	Thin, delicate, and multi-layered quills that are light tan
Flavor	Strong, spicy, and pungent	Mild, sweet, with floral and citrus notes
Price	Less expensive and widely available	More expensive and found in specialty stores
Best for	Occasional use in savory dishes or robust baked goods	Frequent use, daily consumption, or delicate desserts

What to do if you suspect a cinnamon issue

If you experience adverse effects after consuming cinnamon, it is important to take appropriate steps. Stop consumption immediately and consult your healthcare provider. Your doctor may recommend adjusting your dosage, switching to Ceylon cinnamon, or avoiding the spice entirely. For those with known allergies, carrying an epinephrine auto-injector is crucial in case of a severe reaction. Always inform medical professionals about any supplements you are taking, as they can interact with other medications.

Conclusion: Safe consumption and awareness

While cinnamon offers health benefits, it is not without risks, especially in high doses or for sensitive individuals. The key to enjoying this versatile spice safely lies in understanding the difference between Cassia and Ceylon cinnamon and being aware of personal health factors. For those who enjoy cinnamon frequently or for potential therapeutic purposes, choosing the safer Ceylon variety is a wise decision to minimize coumarin-related liver risks. Always prioritize your health by consulting with a medical professional before introducing any significant dietary changes or supplements, including cinnamon.

Frequently Asked Questions

Yes, excessive and prolonged intake of Cassia cinnamon, the most common type, can cause liver damage due to its high coumarin content. People with pre-existing liver conditions are at a higher risk.

If you are on blood-thinning medication like warfarin, you should exercise caution. Cassia cinnamon contains coumarin, a natural anticoagulant, which can increase the risk of bleeding. Consult your doctor before consuming it.

Yes, individuals with diabetes should be cautious. Cinnamon can lower blood sugar levels, and large amounts or supplements could cause hypoglycemia (low blood sugar) if you are already taking diabetes medication.

Symptoms of a cinnamon allergy can include mouth sores, swelling of the lips and tongue, skin rashes, itching, and digestive issues like nausea. In severe cases, it can cause anaphylaxis.

While small amounts used in food are likely safe, pregnant and breastfeeding women should avoid large quantities or supplements due to a lack of safety research and potential risks.

Ceylon cinnamon is often labeled 'true cinnamon' and has a mild, sweet flavor with minimal coumarin. Cassia is typically the more common, cheaper variety with a stronger flavor and high coumarin levels. Check the label or origin.

Children are more sensitive to coumarin. While small amounts in food are generally fine, regular high doses of Cassia cinnamon should be avoided. Parents should be particularly cautious with cinnamon supplements.