Objective To observe the therapeutic effect and mechanism of modified Banxia Baizhu Tianma Decoction [Pinellia

White Atractylodes and Gastrodia Decoction

decoction of Banxia（Rhizoma Pinelliae）

Baizhu（Rhizoma Atractylodis Macrocephalae） and Tianma（Rhizoma Gastrodiae）] for vertebrobasilar insufficiency（VBI）-associated vertigo.Methods Totally 120 cases of VBI were randomized into the treatment group and control group

with 60 in each.Both groups were given betahistine and citicoline sodium on the basis of routine treatment.The treatment group was added with modified Banxia Baizhu Tianma Decoction.One treatment course lasted for 14 days.The therapeutic effect was observed after 2 treatment courses.The peak-systolic velocity（Vp）

end-diastolic velocity（Vd） and mean velocity（Vm） of vertebral artery（VA） and basilar artery（BA） were examined with transcranial doppler（TCD） before and after treatment.The change of hemorheology was detected.Results The total effective rate of the treatment group and control group was 90.00% and 73.3% respectively

with a significant difference between groups（P<0.05）.The Vp

Vd and Vm were significantly increased in both groups after treatment（P<0.01）.The Vd and Vm in the treatment group were significantly higher than those in the control group after treatment（P<0.01）.There was no significant difference between groups in the Vp after treatment（P>0.05）.The hemorheological indexes were significantly improved in the treatment group after treatment（P<0.01）.There was no significant difference in hemorheological indexes between before and after treatment in the control group（P>0.05）.Comparing with the control group

the hemorheological indexes were significantly improved in the treatment group after treatment（P<0.01）.Conclusion Banxia Baizhu Tianma Decoction is effective for VBI-associated vertigo.The mechanism may be related to improving hemorheology and increasing Vd and Vm.