How can ginger help with motion sickness?

Benefit of ginger. Ginger contains a substance which is thought to promote peristatlis (contaction of the intestines in a forward motion) and to stimulate gastric secretions. It essentially functions as an antinausea agent without any sedating effects.
Actually yes. A medical study done in denmark and published in the british medical journal lancet showed convincing evidence that it does help. Ginger has been a traditional remedy for years. In reasonable doses, it should not be harmful. Of course, there are other treatments as well, including dramamine (dimenhydrinate) patches.