Motion sickness is a well known nausea and vomiting syndrome whose physical signs occur during travel by sea, automobile, airplane, and space. This review describes current concepts concerning the aetiology, nature and therapy of this common phenomenon. Motion sickness involve a neural mismatch or confusion between the vestibular, visual, and proprioceptive systems. Therapy is directed towards decreasing conflicting sensory input, controlling nausea, and speeding the process of adaptation.