Cinnamon is a widely popular spice. However, if consumed in excess, it may cause side effects due to its coumarin content. In some cases, it can cause liver damage or trigger an allergic reaction.

Cinnamon is a spice made from the inner bark of the Cinnamomum tree.

It’s widely popular and has been linked with health benefits like improved blood sugar control and lowering of some risk factors for heart disease

The two main types of cinnamon are:

  • Cassia: Also called “regular” cinnamon, this is the most commonly used type.
  • Ceylon: Known as “true” cinnamon, Ceylon has a lighter and less bitter taste.

Cassia cinnamon is more commonly found in supermarkets, given that it’s much cheaper than Ceylon cinnamon.

While Cassia cinnamon is safe to eat in small to moderate amounts, eating too much may cause health problems because it contains high amounts of a compound called coumarin.

Research has found that eating too much coumarin may harm your liver. Research suggests the limit should be about 0.1 milligrams (mg) per 1 kilogram (kg) or 2.2 pounds (lb) of body weight.

Furthermore, eating too much Cassia cinnamon has been linked to many other side effects.

Here are six possible side effects of eating too much Cassia cinnamon.

Cassia (or regular) cinnamon is a rich source of coumarin. However, research suggests that eating too much coumarin may cause liver toxicity and damage.

Some people have experienced mouth sores from eating products that contain cinnamon flavoring agents. This is called cinnamon stomatitis.

Cinnamon contains cinnamaldehyde, a compound that may trigger an allergic reaction when consumed in large amounts.

Having chronic high blood sugar is a health problem. If left untreated, it may contribute to diabetes, heart disease, and many other health problems.

Cinnamon is well-known for its ability to lower blood sugar. Research has found that the spice can mimic the effects of insulin, a hormone that helps remove sugar from the blood, which can help lower insulin resistance.

However, while eating a bit of cinnamon may help lower your blood sugar, eating too much may cause it to fall too low.

While there’s no research evidence to suggest that this has occurred to anyone who has consumed cinnamon, in theory, it is possible to develop hypoglycemia. This can lead to tiredness, dizziness, and possibly fainting.

People who are most at risk of experiencing low blood sugar are those taking medications for diabetes. This is because cinnamon may enhance the effects of these medications and cause your blood sugar to fall too low.

Eating too much ground cinnamon in a single sitting may cause breathing problems if you accidentally inhale some of it, especially in children.

Since the “cinnamon challenge” has become wildly popular, many have attempted to eat large amounts of dry cinnamon.

This challenge involves eating a tablespoon of dry, ground cinnamon in under a minute without drinking water. While it may sound harmless, the challenge can be very dangerous.

Eating dry cinnamon can irritate your throat and lungs, as well as make you gag or choke. This is because the spice has a fine texture that can make it easy to inhale.

It can also permanently affect the function of your lungs. This is because the lungs cannot break down the fibers in the spice. It may accumulate in the lungs and cause lung inflammation, known as aspiration pneumonia.

If aspiration pneumonia is left untreated, the lungs may become permanently scarred and possibly collapse.

People with asthma or other medical conditions that affect breathing need to be especially careful of accidentally inhaling cinnamon.

Cinnamon is safe to eat in small to moderate amounts with most medications.

However, taking too much may be an issue if you’re taking medication for diabetes, heart disease, or liver disease. This is because cinnamon may interact with those medications, either enhancing their effects or intensifying their side effects.

For example, if you’re taking medications that may affect your liver, such as acetaminophen (Tylenol) or statins, excessive intake of the coumarin in cinnamon may increase the chance of liver damage.

Also, the spice may enhance the effects of diabetes medications and cause your blood sugar to fall too low. It’s important you speak with your doctor if you take these drugs, and cinnamon is a frequent part of your diet.

Cinnamon is generally safe to use in small amounts as a spice.

This mostly applies to Cassia cinnamon because it’s a rich source of coumarin. Conversely, Ceylon cinnamon contains only trace amounts of coumarin.

The coumarin content of ground Cassia cinnamon may range between 0.1–3.5 milligrams (mg) per gram (g) of cinnamon, depending on the consistency of the sample.

According to a guideline set by the European Food Safety Authority (EFSA), the tolerable daily intake of coumarin is about 1.5 mg for an adult weighing 60 kg or 132 pounds (lb). A 2021 study also recommends not going over 0.1 mg/1 kg or 2.2 lb of body weight

In the United States, the US Department of Agriculture suggests that half a teaspoon of cinnamon a day or less is generally safe and may even be beneficial to health.

What does cinnamon do to the body?

As long as you consume it in moderation, cinnamon may help keep you healthy by helping:

  • reduce inflammation
  • protect against heart disease
  • improve insulin sensitivity
  • lower blood sugar
  • lower cholesterol
  • protect against infections

Learn more: 10 evidence-based health benefits of cinnamon.

What are the side effects of cinnamon in pregnancy?

There isn’t much known about the effect on a fetus from consuming cinnamon during pregnancy or nursing. Consuming small amounts probably won’t cause any harm, however. Stick to the recommended 0.1 mg of coumarin per 1 kg or 2.2 lb of body weight or about half a teaspoon a day.

Can you overdose on cinnamon?

There’s no research to suggest you can overdose on cinnamon. The concern with eating too much cinnamon relates to its coumarin content, which in excessive amounts, could increase your chance of liver damage.

Sticking to no more than half a teaspoon daily is also a good idea because different types and brands of cinnamon might have different quantities of coumarin in them.

Cinnamon is a delicious spice linked to many health benefits.

In most cases, eating small amounts of cinnamon won’t cause any harm.

On the other hand, Ceylon or “true” cinnamon only contains trace amounts of coumarin.

While eating too much cinnamon may have some drawbacks, it’s a healthy spice that’s safe to eat in small to moderate amounts. Eating less than the tolerable daily intake is more than enough to provide you with its health benefits.