The edema period after a brain hemorrhage is usually 3 weeks, or even 4 weeks. There are several periods to go through: the first is the period when brain hemorrhage reappears, within 1-3 days after the brain hemorrhage, and this period is the most dangerous because it is very likely to lead to the occurrence of another brain hemorrhage. The second is the peak period, which is 10-14 days after the cerebral hemorrhage. This is the peak period of cerebral edema, which must be taken seriously and treated with relevant drugs. As long as the peak period is passed, the later series of treatment will be relatively easy. The main causes of edema are: 1) mechanical compression after cerebral hemorrhage; 2) release of inflammatory mediators. Because brain hemorrhage in the process of absorption will release a large number of inflammatory mediators, resulting in changes in vascular permeability, too much fluid in the blood to spread around the skull and brain, thus forming the situation of cerebral edema, must be actively dehydration, lowering cranial pressure treatment.