Sudden nausea can be caused by physiological factors, but also by digestive and neurological factors. 1. Physiological factors: women during pregnancy will have nausea, vomiting symptoms, usually morning nausea, dry heaving, vomiting, often around the sixth week of pregnancy. If women of age have a history of menopause, it is recommended to improve the ultrasound and other examinations to clarify. 2. Digestive system diseases: chronic inflammation of the gastric mucosa can lead to chronic gastritis, followed by epigastric discomfort, nausea and a series of symptoms; Helicobacter pylori infection, excessive gastric acid and other factors can lead to peptic ulcer, resulting in nausea, vomiting, abdominal pain and other symptoms; intestinal obstruction of intestinal contents through the obstacle to vomiting, abdominal distension, stop defecation and exhaustion and other symptoms. 3. Neurological diseases: migraine patients may suffer from nausea and vomiting during the onset of pain; infection of brain parenchyma by bacterial or viral pathogens may cause fever, headache, nausea, vomiting and other symptoms. In addition, other diseases such as motion sickness and Meniere’s disease can also cause sudden nausea. If sudden nausea occurs, it is recommended to go to the hospital after eliminating physiological factors.