The exact cause of mouth cancer is unknown, although tobacco products are thought to play a significant role in about 80 per cent of cases. Risk factors may include:

* Tobacco use
* Regular and heavy alcohol consumption
* Advancing age
* Sun exposure
* Poor diet
* Poor oral hygiene
* Gum disease
* Habitual chewing of the lips or cheeks
* Irritants, such as strong mouthwashes or ill-fitting dentures
* Leukoplakia (light-coloured patches of atypical cells inside the mouth)
* Herpes simplex infection (cold sores)
* Human papilloma virus infection (warts)
* Family history of cancer (genetic makeup).