Syncope caused by vomiting is considered vasovagal syncope because vomiting causes increased activity of the vagus nerve, which inhibits the sympathetic nerve in the body, and the vagus nerve and sympathetic nerve inhibit each other. If the vagus nerve is enhanced, it will inhibit the sympathetic nerve, causing peripheral vasodilation and a drop in blood pressure, while the heart rate slows down, leaving the brain in a sudden state of ischemia and syncope, so it is called vasovagal syncope. Vomiting accompanied by syncope does not exclude the possibility of other diseases, such as cerebrovascular accidents, i.e., the possibility of stroke. Therefore, it is recommended that patients with vomiting-induced syncope go to the hospital for examination as soon as possible, because if vasovagal syncope is present, the diagnosis can be confirmed by doing an upright tilt test at the hospital. If it is a stroke, a cranial CT can also be done to rule it out. If vasovagal syncope is considered, it usually does not require special treatment and has a good prognosis, as long as the corresponding factors are usually avoided, such as hunger, alcoholism, and working at height, and physical exercise is strengthened to avoid prolonged strenuous activity. If the attacks are very frequent, hospital consultation is recommended.