Unexplained vomiting may be due to pharyngeal irritation, early pregnancy reaction, gastroesophageal reflux and so on. 1. Pharyngeal irritation: such as smoking, odor, dust, difficult to eat food, foreign objects touch and other reasons can cause the occurrence of vomiting reaction, which is a physiological process. 2. Early pregnancy reaction: generally only occurs in pregnant women, due to a substantial increase in serum HCG, causing nausea, vomiting, dizziness, fatigue and other early pregnancy reaction, generally can be initially determined through the early morning pregnancy test paper test morning urine, positive indicates that there may be pregnancy. 3. Gastroesophageal reflux: common symptoms include acid reflux, heartburn, etc. Stomach contents may irritate the pharyngeal nerves and cause vomiting when they rise up the esophagus. There may be other reasons for unexplained vomiting, so you can go to the hospital to complete the relevant examinations to clarify the situation.