Mouthwash and poor dental hygiene may increase the risk of oral cancer

A recent study suggests that poor dental hygiene and excessive use of mouthwash containing alcohol could increase the risk of oral cancer. The study, published in the journal Oral Oncology is based on European research conducted by the Leibniz Institute for Prevention Research and Epidemiology with help from Glasgow University’s Dental School.


Listerine, one of the most well-known brands of mouthwash, has one of the highest percentages of alcohol.

Each year more than 640,000 people worldwide are diagnosed with oral cancer, which can occur in the tongue, the floor of the mouth, the gum and the cheek. Oral cancer is the largest group of those cancers which fall into the head and neck cancer category. The largest risk factors for oral cancer are tobacco and alcohol. Other potential risk factors are more difficult to link causally to oral cancer, because people who smoke and/or drink also tend to neglect dental hygiene.

In mouthwash, alcohol is usually the primary carcinogen of interest, and there is no known harm from non-alcohol-containing mouthwashes. Listerine is one of the most well-known brands of mouthwash, and also has one of the highest percentages of alcohol with 21% – 26.9%. Colgate mouthwash has a lower alcohol content than Listerine, but still contains 15.3% alcohol, which is more than most bottles of wine. The potential risks associated with the alcohol content of mouthwash have prompted many manufacturers (including Listerine and Colgate) to release alcohol-free varieties. Note: the association between mouthwash and oral cancer was only significant when looking at very frequent use (three times a day) — very few people used mouthwash so frequently, thus the risk estimate is consequently less reliable.

As part of a good dental hygiene regimen, regular trips to the dentist can not only reduce the risk of oral cancer, but also potentially aid in the early detection thereof through oral cancer screening, which is usually available from dentists but seldom ordered by patients.

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