Fifty female rats were used in the experiment. With rotation model, Yunfujing was shown to inhibit nystagmic response of rats. The inhibitory effect was 20-30 times stronger than that of Mihuanjun. In Coriolis test, the tolerance time of vestibular stimulative response was taken as a parameter for judging drug efficacy in 32 male volunteers. Following oral administration of Yunfujing at a dose of 400 mg, the tolerance time of vestibular stimulative response was prolonged significantly from 411.34 to 759.63 s. In the mean time, no changes of blood pressure and pulse were observed in the treated group.