There are many reasons for the baby’s lips to be upturned, which may be caused by the infection of the lips and mouth, and may also be adenoid hypertrophy, trauma, pacifier and genetic factors. 1. Lip infection: If the baby lip viral infection, can cause localized lip upturning. It can also be accompanied by swelling, pain and other symptoms. 2. Adenoid hypertrophy: due to the baby’s long-term open-mouth breathing, affecting the development of the facial bones, can also lead to lip upturning and other situations. 3. Trauma: If the baby accidentally touches the upper lip when playing, it can cause the upper lip to swell and appear the situation of lip upturning. 4. Containing pacifiers: If the baby’s posture is incorrect, sleeping with a pacifier can lead to the situation of the lips curling up. 5. In addition, some of the baby lips are due to genetic factors, does not affect the normal growth and development, will not affect the normal chewing ability and respiratory function. It is recommended that babies with chubby lips go to the hospital in a timely manner, after the relevant examination under the guidance of a specialist.