Symptoms occur as a result of prolonged and perhaps violent movement of a kind to which one is unaccustomed, as in a bus, car, boat or aircraft. The cause is overstimulation of the organ of balance, and confusion because the organ receives unusual information from the other organs necessary in keeping one’s balance: eyes, joints and muscles. This results in dizziness, nausea, often vomiting and sweating. Not everybody suffers to the same extent; the symptoms can be increased by apprehension or fear. Habit usually causes the symptoms to diminish, only two per cent of people never become accustomed to a particular unusual movement. Habituation diminishes after the movement stops, however, so that motion sickness can recur. Also, becoming accustomed to one movement does not necessarily enable one to cope with others. The best way to control motion sickness is by prevention. Many preparations are available from chemists; they can prevent nausea, but may make the patient sleepy, so they must not be used by car drivers. There are also plasters available containing a motion sickness remedy; wearing the plaster behind the ear gives protection against motion sickness for a few days.