Large cerebral infarcts can be treated with thrombolysis, but the risks to the patient must be carefully weighed against the benefits obtained. Patients should always be carefully evaluated if they are older than 80 years of age, have a severe cerebral infarction, have an NIHSS score greater than 25, or have imaging evidence of ischemic damage to greater than 1/3 of the middle cerebral artery supply area, and have a previous history of diabetes mellitus. Thrombolysis should not be given if the risk outweighs the benefit, because thrombolysis may lead to cerebral hemorrhage, which can be life-threatening in severe cases. If the patient has a large cerebral infarction due to posterior circulation artery occlusion, thrombolysis can be used in this group of patients because thrombolysis is the only resuscitation method.