What is Coumarin?

Mary McMahon
Mary McMahon

Coumarin is a chemical compound which is found naturally in some plants, although it can be synthetically produced as well. It has a distinctive odor which has led people to use it as a food additive and ingredient in perfume. Due to concerns about coumarin as a potential liver and kidney toxin, its use as a food additive is heavily restricted, although it is perfectly safe to eat foods which naturally contain the compound.

Tonka beans, a natural source of coumarin.
Tonka beans, a natural source of coumarin.

The chemical name for coumarin is benzopyrone. The distinctive sweet odor reminds many people of freshly cut grass or hay, and it has been used in perfumes since the late 1800s. In a pure form, this compound has a crystalline structure, and it is said to taste faintly like vanilla. When ingested, it acts as a blood thinner, and it also appears to be effective in treating some tumors. Coumarin has fungicidal properties as well. However, other much safer substances can be used for all of these purposes, although the compound is sometimes used in combination with other blood thinners for medical treatment.

Cherries naturally contain coumarin.
Cherries naturally contain coumarin.

One natural source of coumarin is tonka beans, tropical beans which are known by the French as coumarou. To release their captive coumarin, the beans are soaked in alcohol and then fermented. The substance also occurs in sweet clover, strawberries, cherries, bison grass, woodruff, and apricots. Coumarin has traditionally been used as a vanilla substitute in various foods, especially tobacco, although this usage is restricted in some countries.

Coumarin has been used as a vanilla substitute in some products, like tobacco.
Coumarin has been used as a vanilla substitute in some products, like tobacco.

Some traditional foods are made with plants which contain coumarin, and it is clearly an important flavor compound in the food since these foods are prepared in a way which concentrates the natural substance. In both Poland and Germany, plants like woodruff are added to alcohol to make a beverage with a distinctive fresh, spring-like flavor which can probably be credited to the coumarin. These products are not generally dangerous to consume, although people may want to avoid consuming high volumes of these foods; the same goes for therapeutic coumarin or derivatives which may be prescribed by a doctor.

Coumarin is a popular ingredient in perfumes.
Coumarin is a popular ingredient in perfumes.

In plants, coumarin appears to act as a natural pesticide, cutting down on insects so that the plant can grow undisturbed. Some chemicals in this family have been harnessed for their pesticide uses, and some related chemicals are even used for larger pests like rodents. Consumers may be familiar with one chemical in the family; warfarin is a popular anticoagulant which can be ingested or injected, depending on the needs of the patient.

Apricots offer a natural source of coumarin.
Apricots offer a natural source of coumarin.
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

You might also Like

Readers Also Love

Discussion Comments


Coumarin was widely used as medication in Europe and Australia in way higher doses than could possibly be found in foods. My prescription is 800/mg (pure) coumarin/day! I've taken it for over 20 years with absolutely no liver problems.

Even in clinical trials that purposely "killed" it for FDA approval, only 6 percent had a liver reaction -- actually, previously called a "pseudo" liver reaction. It disappeares as soon as drug discontinued and usually also with continued use. I'm so sad it's not available now as it helped my lymphedema like nothing else! It's too cheap for the drug industry I guess. But folks, to fear it as naturally occurs in foods is silly.


I am allergic to coumarin but am not sure where you will find this ingredient. Does it hide in food and shampoos or will it be listed as an ingredient? What foods will it be in? Not much information on this allergy so would be grateful for any help.


Cassia caused my creatinine levels to rise to 1.88 up from 1.3 kidney biopsy was the next step. Took 800mg to 4000mg for glucose regulation multiple times a day.


I just bought some Jason "pure natural" restorative Biotin Pure Natural Shampoo with coumarin as the next to last ingredient, which is perfume!

I'm taking it back for a refund. My hair is falling out! So what do you use? This is crazy to say the least. Aubrey seems to be one of the "cleanest" lines at the health food stores.


How can I test a plant's coumarin content?


The only medically recognized adverse symptoms of naturally occurring coumarin are related to allergic sensitization.

The substance can be modified into an anticoagulant by certain fungi, but as a component of food is regarded by German health authorities as harmless unless sensitization occurs, often through overconsumption. People with allergies to strawberries, cherries, or almonds should be advised to avoid coumarin.


I almost died from bleeding in the intestines caused by an "unknown biotoxin." I also lost my senses of smell and taste. Doctors could not help me.

After three years of suffering, I discovered the culprit to be the coumarin in Trader Joe's Lavender Hand and Body Lotion. If I use that product, a few hours later I experience dizziness, loss of vision, and a strange feeling in my blood. Vitamin K is the only 'treatment' that helped me. I had to be my own doctor.


I was using the cassia cinnamon in my coffee to cut sugar. I developed uterine bleeding and cramping. At 59 that is scary. I had every test and all was negative and was getting ready to schedule a hysterectomy as it would not stop when I found an article about it. It is getting better now. It has been a week and it about 95 percent better. I do not know how long it will take to heal. But I assume it will. So much better now!


I added cassia( the common faux cinnamon which is higher in coumarin) to my tea and coffee at a rate of a rounded half teaspoon, taken twice a daily.

Developed nocturnal leg/foot cramps, to the point where sleep was impossible. My nights could only be described as dreamless torture.

Stopped the cinnamon, the cramps are almost gone and mild when they strike. I'm still in the wash out period. It's only been two nights its since it's been discontinued, so I am hoping for complete remission of cramping. We'll see.


I had a very bad reaction with coumarin which is used in Weleda Sage Deodorant. A rash under armpits with redness, burning and itching. Confirmed my a Dermatologist.


Levels of this substance are higher in cheaper Cinnamon from places like Sumatra. Coumarin levels are limited in Germany in foodstuffs and will be in 2011 from the UK.


coumarin occurs naturally in foods and it is said it is not harmful. Is more investigation needed in this? SAVM


Ff coumarin gets in your hair, it could result in hair loss and eventually your hair will fall out. You will notice hair loss within a few weeks.


has anyone ever been found to be highly allergic to this substance, coumarin?

I had a recent reaction after it was used on my hair as a conditioner. i am looking for more information.


Coumarin can be found on its own, or in combination with sugar know as coumarin glycoside. In medical field it was discovered that coumarin glycoside has the blood thinning and tumor thwarting ability.

Post your comments
Forgot password?