Editing Colonoscopy (section)

===Preparation===
[[File:polyethylene glycol container.jpg|thumb|alt=A container of PEG (polyethylene glycol) with electrolyte used to clean out the intestines before certain bowel exam procedures such as colonoscopy.|A container of PEG ([[macrogol|polyethylene glycol or macrogol]]) with electrolyte used to clean out the [[intestines]] before certain [[bowel]] exam procedures such as a colonoscopy.]]

The colon must be free of solid matter for the test to be performed properly.<ref name="pmid25239068">{{cite journal | vauthors = Johnson DA, Barkun AN, Cohen LB, Dominitz JA, Kaltenbach T, Martel M, Robertson DJ, Boland CR, Giardello FM, Lieberman DA, Levin TR, Rex DK | title = Optimizing adequacy of bowel cleansing for colonoscopy: recommendations from the US multi-society task force on colorectal cancer | journal = Gastroenterology | volume = 147 | issue = 4 | pages = 903–924 | date = October 2014 | pmid = 25239068 | doi = 10.1053/j.gastro.2014.07.002 | publisher = Elsevier BV | doi-access = free }}</ref> For one to three days, the patient is required to follow a [[Low-fiber diet|low fiber]] or clear-liquid-only diet. Examples of clear fluids are [[apple juice]], chicken and/or beef broth or [[Bouillon (broth)|bouillon]], [[lemon-lime]] [[Soft drink|soda]], lemonade, [[sports drink]], and [[Drinking water|water]]. It is important that the patient remains hydrated. Sports drinks contain [[electrolyte]]s which are depleted during the purging of the bowel. Drinks containing fiber such as [[prune]] and [[orange juice]] should not be consumed, nor should liquids [[Food colouring|dyed]] red, purple, orange, or sometimes brown; however, cola is allowed. In most cases, [[tea]] or [[coffee]] taken without milk are allowed.<ref>{{cite web |title=Preparing for Your Colonoscopy: Types of Kits & Instructions |url=https://my.clevelandclinic.org/health/treatments/22657-colonoscopy-bowel-preparation |access-date=9 November 2023 |website=Cleveland Clinic |archive-date=9 November 2023 |archive-url=https://web.archive.org/web/20231109202335/https://my.clevelandclinic.org/health/treatments/22657-colonoscopy-bowel-preparation |url-status=live }}</ref><ref>{{cite journal | vauthors = Parra-Blanco A, Nicolas-Perez D, Gimeno-Garcia A, Grosso B, Jimenez A, Ortega J, Quintero E | title = The timing of bowel preparation before colonoscopy determines the quality of cleansing, and is a significant factor contributing to the detection of flat lesions: a randomized study | journal = World Journal of Gastroenterology | volume = 12 | issue = 38 | pages = 6161–6166 | date = October 2006 | pmid = 17036388 | pmc = 4088110 | doi = 10.3748/wjg.v12.i38.6161 | doi-access = free }}</ref>

The day before the colonoscopy (or [[colorectal surgery]]), the patient is either given a [[laxative]] preparation (such as [[bisacodyl]], [[phospho soda]], [[sodium picosulfate]], or [[sodium phosphate]] and/or [[magnesium citrate]]) and large quantities of fluid, or [[whole bowel irrigation]] is performed using a solution of [[polyethylene glycol]] and [[electrolytes]].<ref>{{cite journal | vauthors = Hung SY, Chen HC, Chen WT | title = A Randomized Trial Comparing the Bowel Cleansing Efficacy of Sodium Picosulfate/Magnesium Citrate and Polyethylene Glycol/Bisacodyl (The Bowklean Study) | journal = Scientific Reports | volume = 10 | issue = 1 | pages = 5604 | date = March 2020 | pmid = 32221332 | pmc = 7101403 | doi = 10.1038/s41598-020-62120-w | bibcode = 2020NatSR..10.5604H }}</ref><ref>{{cite journal | vauthors = Kumar AS, Kelleher DC, Sigle GW | title = Bowel Preparation before Elective Surgery | journal = Clinics in Colon and Rectal Surgery | volume = 26 | issue = 3 | pages = 146–152 | date = September 2013 | pmid = 24436665 | pmc = 3747288 | doi = 10.1055/s-0033-1351129 }}</ref>

The patient may be asked not to take aspirin or similar products such as [[salicylate]], [[ibuprofen]], etc. for up to ten days before the procedure to avoid the risk of bleeding if a polypectomy is performed during the procedure. A blood test may be performed before the procedure.<ref>{{cite web|url=http://www.pamf.org/gastroenterology/ColyteColon.pdf |title=Colyte/Trilyte Colonoscopy Preparation |access-date=12 June 2007 |date=June 2006 |publisher=Palo Alto Medical Foundation |url-status=dead |archive-url=https://web.archive.org/web/20070414032341/http://www.pamf.org/gastroenterology/ColyteColon.pdf |archive-date=14 April 2007 }}</ref>