Vomiting when an infant cries may be caused by muscle spasms, increased nasal discharge, imperfect development of the gastrointestinal tract, gastroesophageal reflux, and so on, and it is recommended to go to the hospital in time to clarify the cause. 1. Muscle spasms: babies are too tense and agitated during crying, which triggers severe muscle spasms, leading to vomiting. 2. Increased nasal mucus: babies cry due to phlegm, respiratory secretion of nasal mucus increased significantly, resulting in varying degrees of nausea, vomiting symptoms. 3. Imperfect development of gastrointestinal tract: Since the gastrointestinal system of infants is not well developed, when there are sharp fluctuations in emotions, gastric dysfunction causes vomiting. 4. Gastroesophageal reflux: Babies with gastroesophageal reflux are prone to nausea, vomiting, acid reflux and other symptoms induced by emotional excitement, which leads to babies vomiting when they cry. There may be other reasons for babies to vomit when they cry, so it is recommended that they go to the hospital in time for a complete examination to determine the cause of the illness and then give targeted treatment or therapy under the guidance of the doctor.