Clinically, there is no such thing as three danger periods for cerebral edema. The danger period for cerebral edema generally refers to the peak of cerebral edema within two to seven days of the onset of the disease. Cerebral edema is mainly caused by trauma, infection, brain tumor and other factors caused by the increase of water in the brain tissue, thus causing the phenomenon of increased brain volume. Cerebral edema usually reaches a peak within two to seven days of the onset of the disease, during which the patient’s condition is more dangerous, and in severe cases, it may induce brain herniation, or even lead to the patient’s death. In the treatment of cerebral edema, drugs such as mannitol can be used to rapidly reduce intracranial pressure and improve the condition, while intravenous injection of human albumin or plasma can be used for treatment to help the patient through the dangerous period. After the cerebral edema gradually subsides, the condition will generally improve gradually. It is recommended that patients with cerebral edema consult a doctor in a timely manner to clearly diagnose the cause of cerebral edema, and then carry out targeted treatment to avoid delays in the condition.