Mouth ulcers are always considered to be related to immune, mental, dietary, trauma, genetic and other factors. 1. Immune factors: Usually when patients are attacked by pathogens, leading to a decline in immunity, mouth ulcers may occur. And the immune response will consume immune protein, thus breaking the oral immune balance, can accelerate the occurrence of mouth ulcers. 2. Mental factors: if the usual mental stress, and also long-term anxiety, tension and other bad emotions, will affect the quality of sleep, but also affect the body’s immune system. In this case, the patient is susceptible to viral attack, which can also induce oral ulcers. 3. Dietary factors: If the usual dietary habits are poor, there is partiality of food, resulting in the body of iron, zinc, vitamin B, folic acid and other nutrients intake is not balanced, can also be induced oral ulcers. 4. Trauma factors: if you often eat sharp food, scratch the oral mucosa, or their own teeth bite, wear orthodontic braces, etc., may damage the oral mucosa, induced mouth ulcers. 5. Genetic factors: oral ulcers are also related to heredity, clinical data show that about 40% of patients have a family history of oral ulcers. Repeated mouth ulcers may also have other reasons, patients should consult the doctor to find out the reasons and then receive treatment. Usually should develop good living and eating habits.