Cerebral vasospasm is caused by different reasons, the improvement time is also different, some can be recovered in a short time, some may take 2 weeks or longer. 1. Physiological factors: Temporary cerebral vasospasm can occur when stimulated by cold, emotional stress, etc. Cerebral vasospasm can be recovered in a short time after keeping warm and relaxing. 2. Disease factors (1) Subarachnoid hemorrhage: it usually occurs 3~10 days after the hemorrhage, which may cause deterioration of consciousness and even accompanied by hemiparesis and other newly appeared focal signs, and should be treated with vasospasm preventive medication as soon as possible, which usually takes 7~14 days. (2) Vasculitis: vasculitis can involve cerebral blood vessels, which can lead to cerebral vasospasm, and need to be treated with hormones, immunosuppressants and other drugs, vasculitis is not effectively controlled before the vasospasm may not be able to get better, so the time is relatively long, and it may be several months. Patients with cerebral vasospasm, should consult a doctor in time, under the guidance of a professional physician for treatment.