Vomiting after a colonoscopy may be a reaction to the gas pumped into the cavity during the colonoscopy or to the anesthesia, which is normal. However, if severe vomiting occurs, the cause needs to be clarified in time and should not be taken lightly. Colonoscopy is a commonly used clinical examination method, before the examination, the patient needs to carry out intestinal preparation, intestinal emptying, with the help of the camera at the front of the colonoscope will be intuitively displayed in the intestinal lumen of the situation on the computer screen, can be intuitively determine the intestinal tract with or without lesions. During the colonoscopy, gas is injected into the intestinal lumen to fill the lumen and observe the intestinal tract. When the patient’s normal intestinal peristalsis is not restored temporarily after the colonoscopy, the gas in the intestines can not be discharged in time, and the patient may experience nausea, vomiting, abdominal distension and other discomforts; some of the patients undergo painless colonoscopy, and need to apply anesthesia medications during the examination, and these medications can also lead to nausea, vomiting and other adverse reactions of the patients after the operation. Therefore, vomiting after colonoscopy is normal. In general, after colonoscopy, most patients’ vomiting symptoms will gradually disappear on their own, and no special treatment is necessary. Medications such as metoclopramide and domperidone can also be used for relief, and the prognosis is generally good. Severe cases need to further exclude other diseases, such as bleeding, perforation and other conditions, ischemic colitis and other diseases. It should be noted that patients need to be under the guidance of a medical professional when applying medication to avoid adverse consequences.