A controlled, double-blind study was carried out to determine whether nystagmus response to optokinetic or vestibular stimuli might be altered by some agent contained in powdered ginger root (Zingiber officinale). For comparative purposes, the test subjects were examined after medication with ginger root, placebo and with dimenhydrinate. Eye movements were recorded using standard ENG equipment and evaluation was performed by automatic nystagmus analysis. It could be demonstrated that the effect of ginger root did not differ from that found at baseline, or with placebo, i.e. it had no influence on the experimentally induced nystagmus. Dimenhydrinate, on the other hand, was found to cause a reduction in the nystagmus response to caloric, rotatory and optokinetic stimuli. From the present study it can be concluded that neither the vestibular nor the oculomotor system, both of which are of decisive importance in the occurrence of motion sickness, are influenced by ginger. A CNS mechanism, which is characteristic of the conventional anti-motion sickness drugs, can thus be excluded as regards ginger root. It is more likely that any reduction of motion-sickness symptoms derives from the influence of the ginger root agents on the gastric system.