Cinnarizine is an anti-histaminic drug which is mainly used for the contol of vomiting due to motion sickness. more...
It acts by interefering with the signal transmission between vestibular apparatus of the inner ear and the vomiting centre of the hypothalamus. The disparity of signal processing between inner ear motion receptors and the visual senses is abolished, so that the confusion of brain whether the individual is moving or standing is reduced. Vomiting in motion sickness is actually a physiological compensatory mechanism of the brain to keep the individul from moving so that it can adjust to the signal perception.
Read more at Wikipedia.org