Committee to advise on tropical medicine and travel (CATMAT). Statement on motion sickness.

The development of symptoms follows an orderly sequence that varies with the intensity of the stimulus and the susceptibility of the individual. The initial symptom is usually discomfort around the upper abdomen ("stomach awareness"), which is followed by nausea and increasing malaise. Concurrently the face or area around the mouth becomes pale and the individual starts to sweat. With rapid worsening of symptoms ("avalanche syndrome") there can be increased salivation, feelings of body warmth, a lightness of the head, and often depression and apathy. Vomiting typically follows.