The symptoms of early oral cancer are usually atypical, and the manifestations may vary when it develops in different locations of the mouth, and are usually not limited to three. Usually, we can determine whether to seek medical treatment in time by self-observation whether there are long-standing ulcers, color or texture changes of oral mucosa, unexplained loosening of teeth or numbness of oral cavity, etc. 1. Oral ulcers: long-standing, long-standing, irregularly shaped and hard basal ulcers often indicate early cancer, and normal oral ulcers will heal themselves within 1-2 weeks. If the oral ulcer is more than 2 weeks and the scope does not become smaller, you should promptly go to the stomatology department for consultation; 2. Oral mucosa color change: the normal oral mucosa color is generally light red, if the color changes to white, crimson or light blue without eating easily stained food, there may be oral lesions; 3. Oral mucosa texture change: especially in the tongue or cheek appears unexplained hard nodes and lumps, especially irregularly shaped hard lumps such as cauliflower-like lumps, generally belong to the early symptoms of oral cancer; 4. Loose teeth or numbness in the mouth: if loose teeth, pain, or numbness in the tongue and upper and lower lips suddenly appear, it may be an indirect symptom caused by the cancer invading the roots of teeth or pressing the nerves.