A study also found poor oral health and failure to have regular dental checks increased the risks.
Smoking and heavy alcohol consumption, particularly in combination, are known to raise the risk of mouth and throat cancers.
Now, a new study carried out by researchers at the University of Glasgow Dental School has identified other risk factors for cancer of the mouth, larynx, pharynx and the oesophagus.
The study of 1962 patients with mouth and throat cancers, with a further 1993 people used as comparison, was conducted in 13 centres across nine countries and supported by EU funding.
People with poor dental care were defined as those who hardly ever or never brushed or visited the dentist and those with persistently bleeding gums.
Researchers found that use of mouthwashes three times plus each day was associated with an elevated risk of developing mouth and throat cancer.
Dr David Conway, Clinical Senior Lecturer at the University of Glasgow Dental School, 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.
"Even if you have got dentures, you should have regular check-ups."