Infant vomiting in the form of jets is common in the following cases: 1. congenital pyloric hypertrophy or stenosis, mostly seen in babies about 20 days after birth, vomiting occurs within about half an hour after each feeding, vomit is milk-like, does not contain milk lumps, the baby’s physical growth and development is backward, poor nutrition, go to the hospital in time for abdominal ultrasound examination, if necessary, surgical treatment. 2. central nervous system infection or intracranial hemorrhage, etc. The baby’s mental state is depressed, drowsy or abnormally irritable, mostly accompanied by high fever, convulsions, head tilted back, etc. The baby should go to the hospital in time to perform head CT and cerebrospinal fluid examination, etc.