Whether or not you can still have a colonoscopy if you have symptoms of vomiting after drinking laxatives depends on your bowel preparation. If vomiting occurs long after drinking the laxative, most of the laxative has already worked and will not affect the bowel preparation, so as long as the bowel is cleaned up, the colonoscopy can be performed normally. If vomiting occurs soon after drinking the laxative, or if vomiting occurs while drinking the laxative, the bowel preparation will be affected, and there is no way to perform the colonoscopy as long as the bowel is not cleaned up, so the bowel preparation is very critical for the colonoscopy. If the patient or examinee is vomiting heavily, report it to the doctor in charge or the nurse in charge, and give additional laxatives if necessary, so that the colonoscopy can be completed at the scheduled time.