The main hazard of transient ischemic attack is to affect the blood supply to human brain and lead to brain cell damage, as follows: 1. Transient ischemic attack, the occlusion of blood supply artery is not treated in time, if it is not relieved for more than 24 hours, it can cause brain cell necrosis, resulting in loss of brain regional functions, such as limb weakness and stroke; 2. Repeated episodes of transient ischemia can lead to damage of higher neurological functions, some patients have emotional or memory impairment, and vascular dementia may occur in elderly patients.