1.Lumps: Unexplained lumps in the mouth or neck (not necessarily painful when touched). 2.Tongue movement and perception: Restriction of tongue movement, resulting in difficulty in chewing, swallowing or speaking, or loss of perception and numbness on the half side of the tongue, the cause should be identified as soon as possible. 3.Jaw bone and teeth: local enlargement of the jaw bone, resulting in facial asymmetry, sometimes combined with abnormal sensation, or loose teeth and other symptoms. 4.Pain and mouth opening restriction: Some oral cancer patients have severe pain of unknown reasons or cannot open their mouth as the first symptom, which should be paid attention to. 5.The most common early symptom of lower lip cancer patients is “blistering” of lower lip, which repeatedly breaks down and crusts and eventually turns into superficial ulcer. The ulcer is infiltrated deeper into the tissue and the surrounding area is hard, and the disease can last for several years. In the ectopic type, the swelling grows outward and can take on a cauliflower shape. Patients should be alerted if the following five conditions occur: The oral cavity that turns white, brown or black suggests that the mucosal epithelial cells may have changed. In particular, the oral mucosa becomes rough, thickened or hardened, and white spots and erythema of the oral mucosa appear. 1.Uncured ulcers: The duration of oral ulcers usually does not exceed two weeks. If symptoms such as burning sensation and pain do not heal for more than two weeks, we should be alert to the possibility of oral cancer. One of the common types of oral cancer is ulcer type, which is manifested as elevated edge, uneven center, covered with necrotic tissue and obvious pain. 2.Significant pain: Oral cancer can be painless or only have local abnormal rubbing sensation in early stage, and pain is obvious after ulceration. With further invasion of nerve by tumor, it can trigger ear and throat pain. 3. Swollen lymph nodes: Oral cancer can easily metastasize to nearby lymph nodes in the neck, sometimes the primary lesion is small and even the symptoms are not obvious, but the lymph nodes in the neck have already metastasized. Therefore, if the lymph nodes in the neck are suddenly enlarged, the oral cavity should be examined. 4.Dysfunction: The tumor may invade the opening and closing mouth muscles and temporomandibular joint, resulting in limited movement of opening and closing mouth. It should be emphasized that although the above symptoms are common symptoms of oral cancer, they are not completely used to determine whether one has cancer or not. It is better to go to hospital promptly after the appearance of the above symptoms for early diagnosis and symptomatic treatment.