Oral cancer is a malignant tumor that occurs in the oral cavity and oropharynx. The oral cavity includes: lips, teeth, and gums; the anterior 2/3 of the tongue; the buccal mucosa; the mucosa of the floor of the mouth; and the hard palate. The oropharynx includes: the posterior 1/3 of the tongue; tonsils; soft palate; and larynx. The main carcinogenic factors of oral cancer are: smoking and alcohol. Other carcinogenic factors of oral cancer include: diet lacking fruits and vegetables; human papilloma virus infection; excessive UV exposure. Clinical symptoms of oral cancer: (The following are the most common symptoms of oral cancer, but the symptoms may be different for each individual) 1. painful non-healing lips; 2. white red lesions on gums, tongue and oral mucosa; 3. lumps on lips, inside the mouth or throat; 4. abnormal bleeding, pain or numbness in the mouth; 5. swelling in the jaw or neck; 6. ear pain, voice 7. pain or difficulty in swallowing or chewing; coughing; other diseases may also show the above symptoms, so it is best to consult your health care provider if the above problems occur.