Infant vomiting is a relatively common pediatric problem that almost all children experience because: the infant’s gastroesophageal sphincter is not mature enough, lying flat for long periods of time, and liquid food is more likely to cause reflux than solid food. Most of such vomiting is physiological in nature. The resulting small amount of milk return or spillage (non-jetting) after feeding is often normal and not clinically significant. Parents also do not need to be particularly stressed. However, parents as well as community physicians need to have the necessary awareness of potentially serious illnesses causing vomiting to avoid delays in referral and diagnosis. Symptoms that require high alert and prompt evaluation at a pediatric hospital include the following: 1. bilious vomiting (green/yellow-green vomit) 2. blood in the vomit 3. bulging fontanelle 4. growth retardation/wasting 5. high fever 6. irritability 7. child smells bad 8. apathy and lack of energy 9. neck stiffness and photophobia 10. persistent vomiting 11. jet vomiting 12. With severe abdominal distension and abdominal pain In general, the causes of the above symptoms can be divided into two categories: surgical and non-surgical. Most of the non-surgical vomiting is relatively benign, such as overfeeding, gastroesophageal reflux disease, milk protein allergy, gastroenteritis, etc., which can be relieved by medication and appropriate interventions. Surgical vomiting (mostly related to congenital developmental malformations), although less common, is often more serious than nonsurgical problems and requires emergency surgical intervention in 20-50% of children, so extra vigilance and prompt treatment are needed. Surgical problems include: 1. Bile is bad: For newborns and infants, any green/yellow-green color in the vomit should be considered surgical first. Careful examination is needed to rule out the possibility of intestinal obstruction. This group of disorders includes: malrotation, congenital atresia, intestinal stenosis, intestinal perforation, congenital megacolon, cricothyroid pancreatic, fecal intestinal obstruction, etc. Bilious vomiting (>1 episode) should be seen promptly to rule out surgical problems. If emergency surgery is needed, it should be performed promptly. Otherwise, it will lead to intestinal loss, death, or short bowel syndrome, which greatly affects the quality of survival of the child. 2. Congenital pyloric stenosis: the incidence is about 1/1000. It is more common in boys. Most of them occur in the first 3 months of life. The etiology is unknown. Hypertrophy of the pyloric muscle layer can lead to gastric outlet obstruction. Such vomiting is manifested by immediate eating and vomiting in the form of jets, and the vomit is milk or milk flaps, without bile. After vomiting, the child feels more hungry. The child loses weight and urinates and defecates less. Prompt medical attention is needed. Both open and lumpectomy treatment techniques are now well established. The efficacy is stable. 3. Intussusception: often occurs in infants and children aged 2 months to 2 years. The standard triad of vomiting, abdominal pain, and jam-like stools is seen in only 10-15% of children. More children present with regular, intermittent brief episodes of abdominal pain (which may be accompanied by vomiting), with each episode occurring about 20 minutes apart. The abdominal pain is more intense, and the child tosses and turns when in pain. The interictal period is more comfortable. Bloody stools often appear after 10 hours of intermittent abdominal pain episodes. Therefore, regular intermittent abdominal pain is more important for early diagnosis in children with intussusception. The prognosis of intussusception has improved dramatically due to the availability of ultrasound screening. The majority of children can be repositioned by air/water enema. Surgical repositioning is relatively safe. However, there are still occasional cases with a long course that produce serious complications and lead to death.