Can your daily mouthwash gargles give you cancer?

A refreshing gargle with Listerine’s Cool Mint mouthwash is a daily ritual for many, promising fresh breath and a cleaner mouth. However, a recent study has raised alarming questions about whether this common oral hygiene product might be doing more harm than good.

A study published in the Journal of Medical Microbiology found that regular use of Listerine could be linked to an increased risk of certain cancers and infections.

“Listerine use was associated with an increased abundance of common oral opportunistic bacteria previously reported to be enriched in periodontal diseases, oesophageal and colorectal cancer, and systemic diseases,” the research found.

How does Listerine risk causing cancer and are other alternatives safe? Let’s take a closer look

The findings

The scientists discovered that the daily usage of the popular mouthwash leads to an abundance of two species of bacterium - Fusobacterium nucleatum and Streptococcus anginosus-  which have been linked to causing cancer.

Fusobacterium nucleatum is a key player in periodontal disease and has been associated with colorectal cancer due to its ability to promote inflammation and tumour growth. This bacterium can invade tissues, thereby influencing overall systemic health.

Whereas, Streptococcus anginosus, part of the Streptococcus anginosus group (SAG), is commonly found in the oral cavity and gastrointestinal tract. It is known for causing abscesses and invasive infections, especially in individuals with compromised immune systems.

It is believed that the alcohol in the mouthwash may increase the level of bacteria inside the mouth, as per the academics. Not only did it accelerate the growth, but the researchers also saw a decrease in a group of bacteria called Actinobacteria, which have previously been found to contribute to the regulation of blood pressure.

The shocking observations were made by researchers while they were studying the impact of daily mouthwash use on STI risk among gay men. As a part of this study, 59 participants used Listerine daily for three months followed by three months of placebo mouthwash or vice versa.

“These findings suggest that the regular use of Listerine mouthwash should be carefully considered. Alcohol-based mouthwashes are widely available. The public may use them daily to tackle bad breath or prevent periodontitis, but they should be aware of the potential implications,” Dr Jolein Laumen, first author of the study told The Telegraph.

Are other mouthwashes safe?

While the study only tests Listerine, Professor Chris Kenyon, a scientist at the Institute of Tropical Medicine in Antwerp, Belgium, who worked on the study, stressed that similar levels of bacteria would likely be found using other alcohol-based mouthwashes.
“Most people should not be using it and if they do use it, they should use the preparations without alcohol and limit the use to a couple of days,” Kenyon told the T_elegraph._

Not only Listerine, the study’s author Professor Kenyon stressed that similar levels of bacteria would likely be found using other alcohol-based mouthwashes. Reuters

Listerine is around 20 per cent alcohol, which according to The Sun, is not enough to destroy the odor-causing and decay-causing bacteria rather, it is used as a preservative ingredient and as a carrier for the other active ingredients in mouthwash.

Instead, the scientists of the study recommend using alcohol-free alternatives as they do not destroy all bacteria in the mouth but rather create a good balance.

Meanwhile, a spokesperson of Kenvue, the company behind Listerine, told the Daily Mail, “Based on our initial review, the published trial lacks several important design controls and adequate rigour to make any conclusions about potential impact on human health."

With input from agencies