Motion Sickness (Seasickness; Mal de Mer) By Adedamola A Ogunniyi, MD, Harbor-UCLA Medical Center Reviewed / Revised Apr 2023 View Patient Education Etiology Symptoms and Signs Diagnosis Treatment Key Points Motion sickness is a symptom complex that usually includes nausea, often accompanied by vague abdominal discomfort, vomiting, dizziness, pallor, diaphoresis, and related symptoms.