Blistering and rotting of the corners of the mouth in children is usually caused by B vitamin deficiency, bacterial or viral infection, and lack of attention to hygiene. 1. Lack of B vitamins: children may have insufficient intake of B vitamins in their bodies due to partial feeding, which may be manifested by symptoms such as redness and vesicles at the corners of the mouth, resulting in blistering and rotting of the corners of the mouth. 2. Infection: When children’s body resistance is low, they are susceptible to bacterial or viral infections, which can lead to blistering and rotting of the corners of the mouth. 3. Not paying attention to hygiene: children do not pay attention to personal hygiene, often like to tongue to lick the corners of the mouth, can also lead to the corners of the mouth blistering and then rotten corners of the mouth. Children’s mouth blistering rotten corners of the mouth, there may also be other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, to give targeted treatment or treatment.