Frequent mouth ulcers, professionally known as recurrent mouth ulcers, the main causes include: 1, lack of vitamins and trace elements: lack of trace elements zinc, iron, folic acid, vitamin B12, etc. can trigger corns; 2, mental stress: work exhaustion, mental tension, mood swings, neurological disorders, etc. can also make mouth ulcers repeatedly patronize; 3, gastrointestinal disorders: repeated mouth ulcers can also reveal Your body is facing the threat of gastrointestinal diseases. From the medical point of view, the performance of many gastrointestinal diseases includes recurrent episodes of mouth ulcers because of gastrointestinal discomfort, which affects the body’s digestion and absorption of many foods, thus affecting the replenishment of many elements; 4. Hormonal fluctuations: Some women will have mouth ulcers every time they have their period or before and after their period, and the pain will still be unbearable when they heal or cure their next period, mainly due to the increase in the level of progesterone in the body and 5. Immune system disorders or immune deficiencies: repeated occurrence of multiple oral ulcers, accompanied by external genital ulcers at the same time or before and after, skin acne, folliculitis, eye discomfort and vision loss should be considered leukoaraiosis; when oral ulcers are accompanied by hair loss, purple spots on the face, joint pain and other symptoms before and after, it may be due to lupus erythematosus; oral ulcers accompanied by persistent fever and frequent infections In case of older patients with long history of oral ulcers, if there are deeper and larger ulcer surface and unexplained lumps in the mouth, they should be alerted to oral mucosa carcinoma.