Blistering inside the lips of young children may be a lack of nutrients, but also may be the manifestation of certain diseases, such as hand, foot and mouth disease, thrush, etc., should be timely consultation to find out the cause of the disease. 1. Nutrient deficiency: some children especially love to eat high calorie sweets, as well as high fat fried food, while eating fresh vegetables, fruits are not enough, which leads to the child’s diet is not balanced, while the lack of a variety of vitamins, which leads to the child’s lips easy to blister. 2. Other pathologic factors: (1) Hand, foot and mouth disease: mostly occurring in children under 5 years of age, manifesting mouth pain, anorexia, low fever, and small herpes or small ulcers on the hands, feet, mouth and other parts of the body. (2) Thrush: If a toddler has blisters on the inside of the lips with tofu scum-like material attached, then it is likely to be the common form of thrush. In addition to the above factors, blistering on the inside of a toddler’s lips cannot be ruled out as being caused by other factors. It is recommended that if physiological causes are ruled out, a doctor should be consulted to clarify the cause of the condition and give targeted treatment.