Brain infarction is irreversible. The brain is the most important organ of the human body, but there are almost no glucose and oxygen reserves in the brain tissue. Therefore, when a patient’s cerebral blood vessels are suddenly blocked it will lead to ischemia and hypoxia in the patient’s brain tissue, and irreversible damage to the brain tissue will occur in about 5 minutes and the brain tissue will die. In this case, the disease is irreversible because of the non-renewable nature of brain cells. However, patients are treated with thrombolysis within 6 hours of the onset of the disease, which is currently considered to be the best way to effectively salvage the ischemic semidark zone. When a patient has a cerebral infarction, the central part of the lesion is irreversibly damaged, but the patient still has an ischemic semidark zone in the central part of the lesion. However, timely restoration of blood flow and improvement of brain tissue metabolism can salvage only functionally altered semidark zone tissue around the infarct, avoiding the formation of necrosis and improving the clinical symptoms of patients.