Children always have mouth ulcers may may be related to genetic factors, dietary factors, immune factors and other reasons. 1.Genetic factors. Children always have mouth ulcers may be related to family history of mouth ulcers, which is closely related to heredity. 2. Dietary factors. If children are partial to food, the body lacks iron, zinc, folic acid and vitamin B and other nutrients, which may affect the mucous membrane of oral cells, resulting in easy to grow mouth ulcers. If they like to eat hard foods, they may scratch the mouth, resulting in mouth ulcers. 3. Immune factors. If the body’s immunity is reduced, it is easy to be attacked by pathogens, resulting in mouth ulcers. In addition, teeth accidentally bite the oral mucosa or have braces and other wear and tear on the oral cavity, is also easy to trigger mouth ulcers. When your baby develops mouth ulcers, you should eat a balanced diet and avoid spicy foods and drink plenty of water. Seek medical attention if necessary and follow the doctor’s instructions.