Whether we’re pressed for time in the morning, afternoon, in between snacks, or in the evening, many of us may reach for the mouthwash when toothpaste or dental floss is nowhere in sight. Although this provides a quick fix to combat bad breath and lingering germs, frequently replacing mouthwash with toothpaste and dental floss could become a deadly habit that we need to spit out. According to a recent study published in the journal Oral Oncology, using mouthwash more than three times a day, paired with poor oral health and irregular dental visits, may lead to an increased risk of oral cancer.

“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,” said Wolfgang Ahrens, professor and deputy director of the Bremen Institute for Prevention Research and Social Medicine, according to Medical Xpress. It has been established that smoking and heavy alcohol consumption, especially in combination, are strongly linked to mouth and throat cancers. In addition, low socio-economic status has also been recognized as a contributing factor. However, a team of researchers at the University of Glasgow Dental School, sought to investigate whether oral health, dental care, and mouthwash were associated with mouth and throat cancer, aside from the commonly known risk factors.

Ahrens and his colleagues recruited about 2,000 patients with mouth and throat cancers, and another 2,000 people used as comparison control subjects in their investigation. The study was conducted in 13 centers across nine countries, and supported by the European Union funding. The researchers set out to determine if new risk factors could be involved in the incidence of oral cancer among this cohort.

After taking into account the causation factors of smoking, alcohol, and socio-economic factors, Ahrens and his colleagues were still able to find a link between poor oral health and an increased risk of mouth and throat cancers. Poor oral health was defined as people who had complete or part dentures and people with persistently bleeding gum problems. Despite common belief, patients who have dentures should make sure they go for regular check-ups since they are more sensitive to oral health issues. "People should not assume that if they wear dentures and have none of their own teeth left, they have no need to see a dentist,” said Dr. David Conway, one of the senior authors of the study and clinical senior lecturer at the University of Glasgow Dental School.

In regard to poor dental care, the researchers found people who hardly ever or never brush their teeth or visit the dentist were more susceptible to oral cancer. Dental visits should be determined by a dentist’s risk assessment. Conway believes if people fall into the low risk category, their visits could be once a year, or even every two years. "It is not a case of 'one size fits all,” he added, the BBC reported. “Visits could be six-monthly, but certainly not five-yearly.”

Lastly, Ahrens and his research team found using mouthwash excessively — more than three times a day — may lead to a higher incidence of oral cancer. This finding provides supporting evidence for a 2009 Australian study that found the alcohol content in mouthwashes allows for carcinogens to penetrate into the mouth lining, increasing cancer risk. The Australian researchers “believe that that there is now sufficient evidence to accept the proposition that alcohol-containing mouthwashes contribute to the increased risk of development of oral cancer.” They also suggest for health care professionals to not recommend the long-term use of alcohol-based mouthwashes.

However, the study presented several limitations as it focused on a cohort of people who have had cancer and tumors, similar to the Ahrens-led study. The participants in Ahrens’ study could have possibly used mouthwash to mask the smell of smoking and alcohol. The researchers admit they were unable to analyze the types of mouthwash used many years go by the participants in the study and advise the possible role of mouthwash as a risk factor would require further research. Although you shouldn’t completely stop using mouthwash, Conway says, "But for me, all that's necessary, in general, is good regular brushing with a fluoride toothpaste and flossing combined with regular check-ups by a dentist."

While we know that people who engage in certain risk factors such as smoking, drinking alcohol, or both, and low socio-economic status, may be more likely than others to develop oral cancer, this study presents new contributing risk factors that could help improve diagnosis and treatment. According to the National Cancer Institute, three out of four people with oral cancer have used tobacco, alcohol, or a combination of both. Over 43,000 Americans will be diagnosed with oral or pharyngeal cancer, and oral cancer will cause over 8,000 deaths.


Aqudo A, Brennan P, Conway D, et al. Oral health, dental care and mouthwash associated with upper aerodigestive tract cancer risk in Europe: The ARCAGE study. Oral Oncology. 2014.

Farah CS, McCullough MJ. The role of alcohol in oral carcinogenesis with particular reference to alcohol-containing mouthwashes. Australian Dental Journal. 2008.