Heavy use of mouthwashes may lead to a higher risk of oral cancer, an expert claims.

Research suggests that people rinsing with such products more than three times a day have a greater chance of developing mouth and throat cancer.

Dr David Conway, a senior lecturer at the University of Glasgow Dental School, said people should not routinely use a mouthwash and stick to brushing and flossing instead.

Poor oral health – one of the reasons people regularly use the rinses – also plays a part in cancer risk, he added.

The research supports an Australian study in 2009, which said there was ‘sufficient evidence’ that mouthwashes containing alcohol contribute to an increased risk of the disease, because they allow cancer-causing substances to penetrate the lining of the mouth more easily.

In the latest study, in journal Oral Oncology, University of Glasgow researchers and European colleagues assessed 1,962 cancer sufferers and 1,993 healthy people in 13 centres across nine countries.

Those with poor oral health, including people with dentures and persistently bleeding gums, were at greater risk, they found.

The study set out to identify risk factors for oral cancers affecting the mouth and larynx, as well as oesophageal cancer of the gullet.

Dr Conway said ‘I would not advise routine use of mouthwash, full stop.

‘There are 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 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.’

He added there may be a link between excessive mouthwash rinsing and people who use it to mask the smell of smoking and alcohol – independent risk factors for oral cancer.