Crooked mouth in babies is related to imitation of others, neonatal birth injury, pediatric encephalitis, and other factors. 1. Mimicry: Babies usually have a strong ability to imitate others, and when they imitate others’ laughter, they may have a crooked smile, but it is usually not accompanied by other symptoms. 2. Neonatal birth injury: Neonatal birth injury is related to narrowing of the mother’s pelvis and overweight of the baby. In case of craniocerebral injury, facial nerve injury, etc., the phenomenon of crooked smile may occur due to facial nerve paralysis. 3. Pediatric encephalitis: Pediatric encephalitis is caused by infectious factors, such as bacteria, viruses, etc. It may also be related to chemical stimulation and toxin stimulation. Encephalitis can cause neurological dysfunction, but also can be manifested as headache, runny nose, vomiting, elevated blood pressure, mental depression, etc., can also be caused by the disease of cerebral nerve disorders, facial nerve paralysis and the emergence of the phenomenon of a crooked smile. 4. other factors: crooked mouth crying syndrome, may cause some of the baby smile crooked mouth. Baby smile crooked mouth, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.