The recurrence of sublingual mouth ulcers may be caused by lack of nutrition, mental stress or medication side effects. 1. Lack of nutrition: If the patient has repeated sublingual mouth ulcers, it may be due to a large lack of vitamins, zinc, iron, folic acid and other trace elements in the body, resulting in a decline in the patient’s immune system, and thus the recurrence of mouth ulcers. 2. Mental stress: If the patient’s work and rest is irregular for a long time, and at the same time there are long-term tension, mood swings, panic and other mental problems, it will also cause the patient’s immune system to reduce the recurrence of sublingual mouth ulcers. 3. drug side effects: if the patient needs chemotherapy or radiotherapy because of the disease, after taking chemotherapy or radiotherapy drugs will lead to a reduction in the number of white blood cells in the body, resulting in damage to the oral mucosa cells, thus repeatedly producing mouth ulcers. When the patient has long-term sublingual ulcers recurring, it is important to consult a doctor in time for examination and treatment for the primary disease.