As children are growing and developing, it is more common for them to fall on the back of the head, and the risk period for children to fall on the back of the head is 72 hours. The back of a child’s head is relatively fragile, and a fall may result in a concussion, cerebellar hemorrhage, or cerebellar contusion. When a child falls on the back of the head, parents must closely observe his or her mental state, and observe whether there is any drowsiness, nausea, vomiting, restlessness, depression, dizziness, headache, projectile vomiting, etc. Usually, symptoms of brain injury will appear within 24 hours. If there are no such symptoms, the child still needs to be observed for about 24-72 hours. If the child does not have any abnormal reaction for more than 72 hours, it can indicate that the danger period has passed. If a child falls on the back of the head and develops nausea and vomiting, parents should take the child to the emergency department of a hospital immediately to avoid serious consequences.