Why does mouthwash burn?

Brian Maurer
May 6, 2021
Hygiene Tips and Recommendations
minute read

Good oral health is essential for more than just a bright smile. Some studies are showing links between gum disease and serious problems like heart disease and cancer.

As your dentist always reminds you, regular flossing and brushing your teeth is vital to maintaining proper oral health. Another great practice in addition to these is the whole swish, gargle, spit routine of using mouthwash.

However, using mouthwash isn't always very pleasant. Sometimes it burns, and you might wonder why. Let's find out!

Types of Mouthwash

First, not all mouthwashes are created equal. You can split mouthwashes into two main groups — cosmetic and therapeutic.

Cosmetic mouthwash is kind of like a band-aid, whereas therapeutic mouthwash is more like medicine. For example, if you have bad breath and use a cosmetic mouthwash, you might enjoy a temporary respite from bad breath and a pleasant taste in your mouth. However, a therapeutic mouthwash will have active ingredients in it that attack and kill the bacteria causing your bad breath, offering a more permanent solution.

Both types of mouthwash offer a viable solution to different problems. If you just want to cover up a garlicky meal, a cosmetic mouthwash will do. However, if you suffer from frequent bad breath (halitosis), a therapeutic mouthwash will offer better results.

Why Does Mouthwash Burn?

Not all mouthwashes burn; it depends on the ingredients found in the mouthwash. Furthermore, some people may be more sensitive to certain ingredients. This means a mouthwash that may produce a burning sensation for one person may not for another.

Let's look at some of the most common culprits of a burning mouthwash.


The most common ingredient that causes that burning sensation is alcohol. Mouthwashes can have different concentrations of alcohol, ranging from about 18-26%. If alcohol is the main culprit, you'll probably notice a more concentrated burning sensation on your tongue around your more sensitive taste buds.

Alcohol also indiscriminately kills bacteria in your mouth. You might think that's a good thing until you realize that there are good bacteria that live in your mouth. They help to strengthen your tooth enamel, prevent tooth decay, and aid in saliva production. Alcohol-free mouthwashes, while they kill less overall bacteria, do a better job of targeting just the bad bacteria and maybe a better solution for you.

Alcohol is also drying, and it is not recommended to use an alcohol-based mouthwash if you suffer from a dry mouth.


However, alcohol isn't the only ingredient that can burn. Menthol, which also appears in some kinds of toothpaste and gum, can make your mouth feel tingly and cold. If your mouthwash contains a particularly high concentration of menthol or you are particularly sensitive, it may also create a burning sensation.

Hydrogen Peroxide

Tooth-whitening mouthwashes often contain hydrogen peroxide. This ingredient fizzes and bubbles and may cause a burning sensation for some people.

Essential Oils

Some mouthwashes may contain essential oils like peppermint (menthol), eucalyptus, and thymol (thyme). Many oils have antifungal and antimicrobial properties that help combat the bacteria in your mouth. Different people will react differently to these oils, and some may experience a mild burning feeling.


Mouthwashes with this ingredient are only available by prescription. Chlorhexidine is particularly effective at controlling plaque and helping to reduce gingivitis (gum disease). A small handful of people may have a severe allergic reaction to chlorhexidine.

Dental Problems

Finally, people who have mouth ulcers, gingivitis, or other active dental problems, may experience discomfort with nearly any type of mouthwash.

Benefits of Using Mouthwash

Your mouth contains a delicate balance of both good and bad bacteria. Bad bacteria are at the root of tooth decay, gum disease, and many other dental problems. Good bacteria are working to keep your teeth strong and healthy. When the bad bacteria begin to overwhelm the good, you start having more problems in your mouth. Killing off the bad bacteria can help maintain a more healthy balance in your mouth.

Furthermore, some mouthwashes provide additional benefits—mouthwashes with fluoride help to strengthen tooth enamel and fight tooth decay. Cetylpyridinium chloride is an ingredient that targets the bacteria that cause bad breath.

Carbamide peroxide or hydrogen peroxide can help whiten teeth over time for a more movie-star smile.

Choosing a Mouthwash for You

One person might find the cooling sensation of menthol to be pleasant. But another may experience a burning sensation and dislike it. That's why it's great that there are plenty of mouthwashes out there to choose from. Pay attention to the ingredients. If you find one to be unpleasant, you can try different formulations until you find one you like.

Keeping a Healthy Smile

It's important to remember that mouthwash is only one tool in the fight against tooth decay and gum disease. While using mouthwash can help, it is not a substitute for flossing and brushing your teeth every day.

Wondering how you are doing with your oral health regime? You can learn a lot by understanding the balance of bacteria that are living in your mouth. Send us a sample, and we'll analyze it for you. You'll get a complete report about the balance of bacteria in your mouth and use it to maximize your oral health!

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