The risk of cerebral hemorrhage is greatest within 24 hours, and it is now believed that most patients turn stable around 1 week. Patients with subarachnoid hemorrhage have the greatest risk of rebleeding within 24 to 48 hours, and the risk of rebleeding decreases after 4 weeks. Most brain hemorrhages increase in size early, generally 17%-38% of hematomas increase within 3 hours of brain hemorrhage, 6%-16% of hematomas increase between 3 and 6 hours, and at most 10% of hematomas increase between 6 and 24 hours. Most hematomas are basically stable, and the shorter the time of onset, the greater the risk of hematoma enlargement, which is the most dangerous, and in most cases hematoma enlargement occurs within 24 hours of cerebral hemorrhage. In addition, the risk period of brain hemorrhage is closely related to the amount of brain hemorrhage and the location of brain hemorrhage. A small amount of brain hemorrhage is usually stable in about 24 hours, while a large amount of brain hemorrhage with brain herniation may last for several weeks. In addition, brain stem hemorrhage is so dangerous that the patient can die within 48 hours. Therefore, patients with brain hemorrhage should rest in bed for 2-4 weeks should rest in bed and avoid emotional agitation, constipation, violent coughing and elevated blood pressure.