In daily life, there are often people who suffer from mouth ulcers, especially those who love to eat spicy and heavy food, once the mouth ulcers appear, a little hot, spicy, fried can not eat; and spray watermelon cream, eat vitamin C tablets and so on are not helpful. In fact, mouth ulcers may also be the precursor of some serious oral diseases, such as oral cancer. So, what kind of mouth ulcers are likely to be oral cancer? How to detect it early? Will recurrent oral ulcers become oral cancer? Recurrent mouth ulcers are recurrent mouth ulcers, which are very common and usually can heal on their own. Moreover, after this kind of ulcer heals itself, it will reappear in other parts of the mouth (i.e. the location of the ulcer is not fixed). This recurrent oral ulcer is actually a disease of the oral mucosa, also known as “mouth sores” and “recurrent aphthous ulcers”. It is not oral cancer and will not develop into oral cancer. It is characterized by variable location and self-healing. Its cause is unknown, and people often think that it is caused by “fire”. Can oral ulcers caused by abrasions or bites develop into oral cancer? Unlike recurrent oral ulcers, such oral mucosal breaks and ulcers caused by abrasions and bites have a clear cause of injury. For example, abrasion by sharp tooth tips or tooth edges; broken by dentures, pierced by fish spikes, burned; or purely unintentional bite …… These ulcers are called “traumatic ulcers” in terminology. After the cause of the injury is removed, it will heal on its own and there is usually no need to worry about oral cancer. However, it is important to note that if the ulcer does not heal after the cause of the injury is removed, you should be alert to the possibility of oral cancer. What kind of mouth ulcers may be related to oral cancer? Some patients may already have oral cancer, but the symptoms of oral cancer are not yet obvious and have not yet been detected. If it happens to come into contact with hard and sharp external force or rubbing, it becomes a cancerous ulcer with abnormal sensation. Therefore, those factors such as friction, stabbing and biting are not the real causes of mucosal breakage, but the factors that aggravate the symptoms of oral cancer. Of course, chronic irritation such as long-term friction may also lead to the occurrence of oral cancer. Therefore, when oral ulcers appear, find the cause and solve these injury-causing causes first, and then observe for a period of time. If there is no tendency to heal, you should be alerted that it is oral cancer. Then, how long to observe? Generally, it is 1~3 weeks.