Tongue ulcers may be caused by poor oral hygiene, trauma, malignant tumors and other reasons. 1. Poor oral hygiene: it may be due to infrequent brushing of teeth, etc., the microorganisms in the mouth multiply a lot and become infected, which leads to the damage of the tongue mucous membrane, and then the tongue ulcer appears. 2. Trauma: It may be due to the long-term abrasion of the tongue surface caused by improperly made denture, excessive wear of teeth, etc., and ulcers appear after the mucous membrane is broken. 3. Malignant tumor: it may be caused by the immune state of the body, gene mutation, long-term smoking and so on. Due to the rapid growth of tumor cells, immature and abnormal growth of blood vessels inside the tumor tissues, some tumor cells may suffer from hypoxia and necrosis, and cancerous ulcers appear on the tongue. It is recommended to go to the hospital in time for the treatment of tongue ulcer and follow the doctor’s instruction to avoid delaying the condition.