The sudden onset of vomiting in a 7-month-old baby can be caused by a variety of reasons. If the baby has no other abnormal symptoms, it is mainly considered to be caused by improper feeding. If the baby also has diarrhea, abdominal pain and other symptoms, consider the abdomen is cold, respiratory infection, gastrointestinal infection and other diseases. 1, improper feeding: 7-month-old baby’s gastrointestinal tract is not fully developed, if there is a one-time feeding more, or feeding eating milk when inhaling a lot of air and so on, can appear sudden vomiting symptoms; 2, abdomen is cold: if the baby abdomen is cold, or ate some colder Supplementary food, there may be a sudden dry vomiting, vomiting situation. At this time, parents do not have to worry too much, usually after sufficient rest will disappear naturally; 3, respiratory tract infection: such as tonsillitis, due to tonsil hypertrophy, swelling, baby dry vomiting symptoms; 4, gastrointestinal infection: if the baby consumed spoiled or contaminated food, gastrointestinal mucosa by viruses, bacteria and other stimuli, sudden vomiting may occur; 5, other diseases: such as acute appendicitis, acute cholecystitis, pancreatitis, intestinal entrapment or intestinal torsion, etc. Relatively speaking, the vomiting caused by these diseases will be more urgent and painful, and the baby will be in a worse state. In addition, if the baby suffers from central nervous system diseases, such as intracranial hemorrhage or encephalitis due to cranial trauma, it may also cause the child’s intracranial pressure to increase, resulting in sudden vomiting.