MODEL RELEASED. Seasickness. View of a woman holding her hand to her mouth on a boat, suffering from seasickness. Seasickness is a form of motion sickness. Motion sickness is due to the effect of repetitive movement on the organ of balance in the inner ear. It varies in severity from a feeling of discomfort to excessive nausea and vomiting. The complaint is usually controlled by the use of antiemetic drugs which reduce nausea.