The peak of cerebral edema caused by cerebral infarction usually starts 24 hours after the onset of the disease and reaches the first peak at 48 hours, after which it persists for two or more weeks. The principle of cerebral edema caused by cerebral infarction is that brain cells undergo ischemia and necrosis, resulting in the formation of a soft focus in the center of the site of occurrence, surrounded by an ischemic semidarkness and edema band. This ischemic edema will begin to appear two hours after the occurrence of cerebral infarction, and thereafter may appear progressive aggravation, reaching the first small peak in 24 hours, and the second peak in 48 hours, which is also the time when the patient’s clinical symptoms are the most serious, and the duration of the patient’s clinical symptoms is generally about two weeks. However, according to the different metabolic ability of patients, different underlying diseases, different age, etc., different time changes can occur. For example, in the case of large cerebral infarction, if the patient is older, and combined with renal or hepatic dysfunction, etc., and the metabolism is slow, the cerebral edema may also last for a month, or even longer.