The pathogenesis of motion sickness includes both inner-ear stimulation by body movement, especially a Coriolis-type stimulus, and optokinetic stimulation due to the shift of the surrounding visual fields. According to Kornhuber, Sakata and others, the vestibular cerebellum also participates in an important way. We conducted this study to elucidate the influence of the vestibular cerebellum on the development of motion sickness. We initially focused attention on the visual suppression test of Takemori et al. as a test for vestibular cerebellar function. We reported a modification of this test, described as postrotatoric nystagmus. We employed this test as a rotatoric visual suppression test using milder stimulus for patients complaining of motion sickness. The pathogenesis and treatment of motion sickness are also discussed.