Sudden vomiting in babies is common in the following situations. First, the normal phenomenon. The baby will occasionally vomit after eating milk, generally in good condition, normal weight gain, belonging to the overflow of milk, with the growth of age, this phenomenon gradually disappears after 6-8 months of age. Secondly, digestive system diseases. When there is acute gastroenteritis, it is easy to vomit, mostly accompanied by abdominal pain, loss of appetite, etc. If necessary, oral antibiotics or antiviral drugs, and probiotics and other anti-infective treatment to improve the intestinal flora. Third, surgical diseases. When there is acute intestinal obstruction, intussusception, congenital intestinal atresia, there will be obvious vomiting with abdominal pain, poor mental state of the baby, crying obviously, need to go to the hospital in a timely manner. Fourth, neurological diseases. When there is cranio-cerebral trauma, intracranial hemorrhage, intracranial infection, there will be jet vomiting, the baby is depressed or irritable, need to promptly seek medical attention.