Alcohol in mouthwash — Does it cause cancer?

Dear Alice,

My boyfriend thinks that mouthwash that contains alcohol is harmful to your gums and causes cancer. Is there any truth to this? Is alcohol harmful in mouthwash?

Thank you,


Dear D, 

There is conflicting research relating to whether or not mouthwash containing alcohol causes cancer. While some studies find no association between cancer and alcohol-containing mouthwash (commonly referred to as antiseptic mouthwash), an increasing number of studies have found a correlation between this type of mouthwash and the development of oral cancer. A possible explanation for this relationship is that when alcohol (in the form of ethanol) is metabolized in the mouth through bacteria in oral plaque, it turns into a substance called acetaldehyde — a known carcinogen, or cancer-causing substance. Acetaldehyde may cause damage to mucus in the mouth, increasing the risk of developing cancer. That being said, cancer typically is caused by a combination of hereditary, genetic, environment, and lifestyle factors. Simply using mouthwash that contains alcohol won’t inherently cause you to develop oral cancer. However, if you have a family history of oral cancer, you may want to consider using alcohol-free mouthwash instead or skipping your mouthwash routine all together. 

Despite contradictions in the research related to cancer and mouthwash, high-alcohol (up to 26 percent alcohol) content mouthwashes have been reported to have other adverse effects, with few overall benefits. Reported side effects of high-alcohol mouthwash include corroded fillings and drying out of the mucosal tissue in the gums and inner cheeks — causing dry or burning sensations in the mouth. Further, mouthwash that contains alcohol may make bad breath even worse over time. This is because alcohol-containing mouthwash eliminates all the bacteria in your mouth, even the beneficial kind of bacteria that helps to fight plaque and infections. Excessive use of this type of mouthwash has also been linked with mouth ulcers and oral pain.  

That being said, not all mouthwashes are created equal! Alcohol-free mouthwashes typically contain no alcohol while still preventing plaque buildup, tooth decay, gum diseases, and bad breath. This type of mouthwash also tends to have more beneficial cosmetic effects on your teeth, such as the color and hardness. This is because, unlike its alcohol-containing counterpart, alcohol-free mouthwash typically targets only the harmful types of bacteria in your mouth, keeping a balance of bacteria in the mouth and preventing further damage. These products typically contain cetylpyridinium (fights bacteria, plaque, and bad breath) or chlorhexidine gluconate (plaque fighter found in prescription mouthwash). Alcohol-free mouthwashes also tend to be gentler on the mouth, reducing the burning sensation typically associated with using mouthwash. Since mouthwash with alcohol may have a high ethanol concentration (for reference, a shot of vodka can contain up to 40 percent alcohol!), alcohol-free mouthwash is typically recommended for those who have a history of alcohol use disorder. 

Several studies have failed to demonstrate a significant advantage to using alcohol-containing mouthwashes over alcohol-free mouthwashes. In fact, alcoholic mouthwashes are no more effective than their alcohol-free counterparts. Indeed, alcohol is often used as an inexpensive preservative in mouthwash to help increase the product shelf life. Although no direct link between mouthwash containing alcohol and cancer has been found, swapping out your alcohol-containing mouthwash for its alcohol-free counterpart may reduce your risk of experiencing any of the side effects associated with mouthwash that contains alcohol. Looking for products that are labeled antibiotic rather than antiseptic can help you find alcohol-free mouthwashes. If you can’t find an mouthwash sans alcohol, you may consider one that has a low alcohol concentration. If you’re still concerned, a trip to your dental professional for recommendations may be a great next move. 

Hope this helps! 

Last updated Jan 29, 2021
Originally published Apr 13, 2001

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