Frequent ulceration inside the mouth belongs to oral ulcers, which may be caused by oral mucous membrane damage, genetic factors, infection and other reasons. 1. Oral mucous membrane damage: it may be caused by direct damage to the oral mucous membrane due to dental calculus, medication, or high food temperature. 2. Genetic factors: When parents have recurrent aphthous ulcers, the child may also be inherited, thus developing recurrent aphthous ulcers. 3. Infections: including viral and bacterial infections, viruses are parasitized in cells, and the immune response caused by the viral antigens produced by the cells can cause pathological changes in the host tissues and the formation of ulcers. It is recommended that patients suffering from mouth ulcers go to the hospital in a timely manner, follow the doctor’s instructions for treatment, to avoid delaying the condition.