Sodium phosphate salts are usually drunk before a colonoscopy, and if nausea and vomiting are present, it is recommended that the medication can be taken in small, frequent doses separately, or switched to other medications such as mannitol oral solution. Sodium phosphate salts need to be taken orally before having a colonoscopy to help the subject clean out the intestinal contents and prepare for the colonoscopy before the procedure. If the intestinal contents are not cleaned up before doing colonoscopy, the intestinal contents will affect the clarity of the field of vision of the colonoscope during the colonoscopy, resulting in not being able to see the intestinal mucosa and missing lesions. If you drink sodium phosphate salt nausea and vomiting, you can take a small number of doses, usually need to drink within two hours, it is recommended that the examinee can take a walk, distraction, to reduce the symptoms of nausea and vomiting; in addition, if the examinee himself has an allergic reaction to the sodium phosphate salt, you can also be guided by the doctor to use mannitol oral solution and other drugs instead. Both sodium phosphate and mannitol may have vomiting side effects. It is important to note that all medications should be taken under the guidance of a medical professional.