Does Mouth Wash Cause Oral Cancer?

A person walks into Wal-Mart with the goal to pick up some toothpaste. As they find the aisle, which contains toothpaste, they come across some mouthwash. She thinks that it cannot hurt to purchase some as the container claims the product cleans your mouth and makes your smile whiter. Although these claims may be true, there may be a danger present in using this mouthwash. Is mouthwash associated with oral cancer?listerine-mouthwash-bottles

40,000 Americans and around 640,000 people in the world are diagnosed with oral cancer annually. The deaths that result from oral cancer are over 7,800 a year.

The ingredients in certain mouthwashes are said to be carcinogenic. Fluoride, formaldehyde, and saccharin, (or common ingredients found in mouthwash) have been suspected to be cancer triggers. The U.S. Environmental Protection Agency claims formaldehyde is a “probable human carcinogen.” Studies in the 1980s revealed that rats exposed to formaldehyde ended up having nasal cancer in fact (but no proof has shown it causes cancer in humans yet).

The Dental Journal of Australia has made the claim that alcohol-based mouthwashes and an increased risk of oral cancers correlate as a result of causation (the mouthwash causes oral cancer).

One study completed by researchers from the University of Glasgow Dental School studied 1,963 patients with cancer of the oral cavity, oropharynx, hypopharynx, larynx or esophagus and then tested another 1,993 people as control subjects from nine different countries. The researchers seemed to find a link between mouthwash and cancer after removing the causation of oral cancer from smoking, alcohol, and low socioeconomic status. Scores were interpreted to analyze oral health and dental care. Odd ratios (which help us identify the probability one thing is associated with another) of low versus high scores of oral health and dental care and confidence intervals were used to adjust for confounding factors. The odd ratios for the absolute frequent use of mouthwash (in which is considered the use of mouthwash 3 or more times a day), was 3.23 with the confidence interval ranging from 1.68-6.19. This proof is very strong as odd ratios over 1 show a strong correlation between two things but only 1.8% of cases and 0.8% of controls reported using mouthwash 3 or more times a day. This information was said to show a link between oral cancer and mouthwash. There needs to be more research however as no known mechanism has been found.

Professor Wolfgang Ahrens, Deputy Director of the BIPS says, “These results are really important. Up until now, it was not really known if these dental risk factors were independent of the well known risks for mouth and throat cancers – smoking, alcohol and low socioeconomic status.” The researchers found, “frequent use of mouthwashes (3-plus times per day) was associated with an elevated risk of developing mouth and throat cancer.”


The Journal of Oral Oncology has gone into depth to discuss whether or not mouthwash is the causation for oral cancer. It analyzed 10 major control case studies that have been performed in the last three decades to observe this phenomenon. Of the 10 reviewed, 7 showed there was no consistent association with mouthwash and oral cancer, while the 3 others had very minor proof to link the two.

In 1991, a study found that the risk of oral cancer was elevated by 40% for males and 60% for female who used mouthwash containing alcohol after adjusting for tobacco and alcohol use. Thus, raising some concern there are many confounding factors linked to raising the risks of cancer. Since then, a handful of other studies have been completed, but they cannot directly prove the causation of oral cancer thanks to mouthwash.

There have been numerous studies in which show there is a connection between cancer and mouthwash but yet again, there are too many confounding variables to be aware of. The numbers in the studies are too insignificant to worry researchers yet. The null hypothesis has not been rejected so far. I would tell people to keep using mouthwash but to limit the use of it to no more than twice as day as little evidence shows high use of the mouthwash shows some concern in elevating oral cancer risks.


3 thoughts on “Does Mouth Wash Cause Oral Cancer?

  1. Hung Chieh Wang

    This is a interesting blog. I wrote a blog before discuss about if mouthwash really work. The result turn out that it does work and can kill bacteria in the mouth. Now I found out that alcohol contained mouthwash can cause cancer. I guess if we really want to use mouthwash, we have to choose the non-alcohol mouthwash. Here is the sources I found also states that alcohol contained mouthwash cause cancer Ask a dentist

  2. Brooke Kaiden

    I was not aware that mouthwash could cause cancer and I found your research interesting. Like you said in your conclusion a lot of your research proves the hypothesis that mouthwash could cause cancer but there are a lot of confounding variables that they get in the way of finding a conclusive answer. I think that it is interesting that something that we put in our mouth is able to kill all of the germs. The advice that was given is good because until there is real direct proof I am still going to use mouthwash because it makes my breath nice and fresh, and I use it pretty often and I never had a cavity or any other teeth problem. I think that now that I heard that cancer could come from mouthwash I will limit my use, just like you said.

  3. Celine Elizabeth Gosselin

    I was writing a blog earlier about keeping your toothbrush bacteria-free, and supposedly rinsing your toothbrush in mouthwash before use doesn’t really help get rid of the germs. It really makes you wonder what mouthwash is really doing for you. Maybe we buy it for the minty taste and how it leaves our mouths FEELING clean afterwards? All I know is that I’ve never used mouthwash in my entire life and I’ve never had a cavity or needed braces. Seems suspicious to me… If mouthwash isn’t really doing anything majorly beneficial for your mouth, why risk cancer?

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