Projectile vomiting is commonly seen in increased intracranial pressure, intracranial tumors, pyloric obstruction, and so on. 1. Increased intracranial pressure: when the intracranial pressure is increased, headache may appear, and when the headache is severe, it may be accompanied by projectile vomiting, and optic papillae edema may also appear. 2. Intracranial tumor: Intracranial tumor can cause different degrees of intracranial pressure increase according to its size, location, growth rate, etc. The higher the pressure is, the more intense the vomiting is. 3. Pyloric obstruction: hypertrophy and enlargement of pyloric ring muscle, jet vomiting, vomit does not contain bile, gastric peristaltic wave can be seen in epigastric region, and olive shaped hypertrophied pylorus can be touched between umbilicus and xiphoid process. The appearance of projectile vomiting, need to immediately go to the hospital to avoid delay.