Experts warn using mouthwash more than twice a day can give you cancer

The “elevated risk” emerged from Europe-wide research into the popular and high-selling breath-freshening product.

Study leader Dr David Conway, from the University of Glasgow, warned: “We have found that using mouthwash excessively – three or more times a day – raises the risk of cancer .

“I know that some people who regularly smoke or drink alcohol use mouthwash to hide the smell.

"I would advise against any excessive use of it.”

He went on: “There are some occasions and conditions for which a dentist could prescribe a mouthwash.

“It could be that a patient has a low salivary flow because of a particular condition or medicine they are taking.

“But unless a dentist has prescribed a mouthwash, personally I think all you need for good oral health is regular brushing with a fluoride toothpaste and flossing, plus regular check-ups by a dentist.”

Dr Conway added: “We did not find any significant increase in risk associated with using mouthwash once or twice a day.”

Smoking and alcohol consumption are established risk factors in oral cancer, which is diagnosed in 5,000 people across the UK each year and causes 1,600 deaths.

The alcohol in mouthwash is thought to help cancer-causing substances such as nicotine permeate the mouth lining.

It can also produce a substance called acetaldehyde, a carcinogen, which can accumulate when swished around the mouth.

The study is published today in the respected specialist journal Oral Oncology.

A woman smiling showing her teeth Risk: A similar study was published in Australian Dental Journal in 2009

 It looked at the cases of 1,962 patients with mouth or throat cancer and at 1,993 people without the disease and was conducted by 13 universities, including Glasgow, across nine countries.

The researchers also found evidence that people with poor dental care – those who never or hardly ever brushed their teeth – also faced an increased risk of developing cancer.

Prof Wolfgang Ahrens, of the Bremen Institute for Prevention Research and Social Medicine in Germany, said: “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 socio-economic status.”

A study published in the Australian Dental Journal in 2009 found that the use of mouthwash increased the odds of oral cancer by nine times in current smokers.

The researchers said that on the basis of their review they “believe 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 said healthcare professionals should not recommend the long-term use of alcohol-based mouthwashes.