Motion sickness.

Motion sickness affects approximately 90 percent of the population at some time during life, and for many the problem is recurrent and severe. Labyrinthine-defective individuals are "immune." Adaptation is highly specific to one type of motion. Recent studies have focused on the role of the limbic system in mechanisms of motion sickness. Medications are sometimes useful, but they have a high incidence of side effects. Oral agents are ineffective after symptoms develop.