Projectile vomiting in a nine-month-old baby may be due to elevated intracranial pressure or gastrointestinal disorders. It is necessary to go to the hospital in time to determine the cause of the disease and treat the cause. Common causes and treatments a, elevated intracranial pressure 1, central nervous system infections: children with central nervous system infections, causing a marked increase in intracranial pressure, there can be jet vomiting, fever, drowsiness, convulsions and other symptoms, the need to reduce intracranial pressure in a timely manner, to clarify the etiology of the infection, the use of mannitol medication can be prescribed by the doctor to alleviate the symptoms, and for the treatment of the etiological agent; 2, craniocerebral injuries and intracranial locoregional lesions: traumatic brain injury, severe hypoxia can cause cerebral hydrocephalus, severe hypoxia can cause cerebral hydrocephalus, and for the treatment of the etiological agent. The severe hypoxia can cause cerebral edema, intracranial hemorrhage, hydrocephalus, brain tumors and other causes of intracranial volume increase, increased pressure, this time we need to consult a doctor in a timely manner, to clarify the cause of the disease, and if necessary, through surgical treatment. Second, digestive diseases 1, gastrointestinal cold: is a virus-induced gastrointestinal dysfunction, cold or improper diet can often induce vomiting, accompanied by stool abnormalities, severe cases can be projectile vomiting symptoms. These children should pay attention to their diet, avoiding raw, cold, hard, spicy, stimulating, greasy food, and pay attention to abdominal warmth. In addition, mild symptoms can be relieved by abdominal massage and moderate exercise. Serious cases need timely medical attention, under the guidance of a doctor; 2, gastroenteritis: due to the baby’s gastrointestinal power is relatively weak, gastroenteritis is more serious when there will be projectile vomiting. In the daily diet should encourage the baby to eat small meals, vomiting serious need to fast, take the baby to the hospital in a timely manner.