Mouth sores are a common oral disease, the causes of mouth sores may be bad habits, mental factors and viral invasion. 1. Bad habits: patients usually do not pay attention to diet, long time consumption of spicy and stimulating food, resulting in malnutrition, lack of b vitamins, iron, zinc, magnesium and other trace elements, which leads to the emergence of mouth sores. 2. Mental factors: patients in the mental overstress, emotional fluctuations, long hours of late-night, will lead to plant nervous system dysfunction, thus triggering aphthous ulcers. 3. Viral invasion: due to herpes stomatitis caused by aphthous ulcers, patients will appear a large number of scattered oral ulcers trauma, Candida infection or fungal infection caused by aphthous ulcers, patients will appear in the corners of the mouth appear white pseudomembrane, the mucous membrane of the tongue congestion and erosion. When patients have mouth sores, they should promptly change their lifestyle habits, pay attention to a light diet, and seek medical attention in time, under the guidance and advice of the doctor.