Objective To evaluate the clinical efficacy and safety of dl-3-butylphthalide (NBP) soft capsules in the treatment of posterior circulation ischemia vertigo (PCIV) due to the hemodynamic effect of one dominant vertebral artery.Methods Seventy-six patients with the first onset of vertigo were selected, among whom PCIV was detected by head magnetic resonance angiography. The PCIV patients were randomly assigned to treatment and control groups, which were given aspirin and atorvastatin calcium therapy and NBP soft capsules combined with aspirin and atorvastatin calcium therapy, respectively. The degree of symptom alleviation and the rate of abnormal transcranial Doppler (TCD) blood flow were measured after 14 days of treatment.Results The overall response rates were 92.1% in the treatment group and 65.8% in the control group, showing a significant difference between groups (P<0.05). The rate of abnormal TCD flow findings in basilar artery decreased in both groups after treatment, and the decrease was higher in the treatment group than in the control group (47.4% vs 57.9%, P<0.05). Conclusions Use of NBP soft capsules is an effective and safe therapy for PCIV caused by vertebral artery dominance.