When the internal carotid artery is occluded on one side, it may cause the blood of the contralateral internal carotid artery to flow into the affected side via the anterior communicating artery; or the blood of the vertebral basilar artery to flow into the internal carotid artery via the posterior communicating artery on the same side; thus, the limb on the same side as the occluded vessel may become paralyzed or have sensory impairment, or the clinical manifestations of insufficient blood supply to the vertebral basilar artery, such as hemiplegia, hemianesthesia, aphasia, etc. The treatment of this disease may include endarterectomy, vascular bypass (bypass), intracranial and extracranial arterial anastomosis, etc., to improve the insufficient blood supply. Vasodilators and antihypertensive drugs are contraindicated because they may lead to aggravation of the phenomenon of “blood theft”. In addition, symptomatic treatment can be combined. Clinical manifestations of recurrent TIA of the internal carotid artery system, such as transient black haze on the side of the lesion, reversible mild hemiparesis, limb numbness and aphasia on the contralateral side; weakened or absent pulsation of the internal carotid artery, and audible vascular murmur.