Mouth ulcers caused by bitten lips are often traumatic ulcers. As long as the bite does not continue, the ulcer can heal in 1 week. To promote ulcer healing, use 0.1% to 0.2% chlorhexidine gluconate solution, 0.5% povidone-iodine solution, 0.1% ezacridine solution, 0.2% ciprochloronium gargle or compounded boric acid solution for mouth rinsing. Topical tretinoin oral cream or recombinant human epidermal growth factor gel is applied topically. If there is a long-term situation of biting the lips to form a mouth ulcer, it is necessary to specifically check the teeth to see if there is a problem with the bite of the teeth, and if the total stimulus in a position of long-term ulcers do not heal for more than a month, then further examination is required. Mouth ulcers caused by bitten lips are often seen in children, mostly caused by bad habits, such as habitual lip biting or self-inflicted ulcers caused by stimulating the mucous membrane of the lips with fingers or foreign objects. For children with self-inflicted ulcers, it is important to correct the bad habits, if not, there may be behavioral problems, some children are suffering from Tourette’s syndrome, if necessary, to ask the pediatrician for joint treatment. For pain relief, compound chamomile lidocaine can be applied locally to the ulcer. To promote ulcer healing, topical trimethoprim oral cream or recombinant human epidermal growth factor gel can be applied topically. For specific medication, please refer to the doctor’s consultation. In addition, you need to pay more attention to oral hygiene, eat more fresh fruits and vegetables, eat a light diet, and avoid bites as much as possible.