Clinically, oral cancer encompasses a wide range of conditions. Early symptoms in patients include the following aspects: many patients experience recurring, hard-to-heal ulcers on the tongue, some manifest ulcerative lesions on the lips, or small nodular lesions which generally do not show obvious symptoms initially. Some patients show symptoms of infection or pain, while others may experience recurring bleeding of the gums, loosening of the teeth, or discomfort in the throat during swallowing. The early symptoms in patients are not typical, leading many to not seek medical consultation early on. It is usually not until they experience severe difficulty in opening the mouth or swallowing, or when the patients have difficulty speaking, that they will seek medical attention.