For most patients, the colonoscopy itself is easy. It is the prep the day before that people worry about. The good news is that a clear plan makes it manageable, and getting the prep right is the single most important thing you can do for an accurate exam. A clean colon lets me see the lining clearly and find or remove polyps before they become a problem. Here is what to eat, what to avoid, and what to expect from start to finish.
Why Prep Matters So Much
During a colonoscopy, I examine the entire lining of the colon. If stool is left behind, it can hide polyps or other findings, and the exam may have to be repeated. A good prep is what makes the difference between a thorough exam and an incomplete one.
A Few Days Before
About three to five days before your exam, switch to a low-residue diet, which means cutting back on high-fiber foods like raw vegetables, whole grains, nuts, seeds, and corn. These take longer to clear from the colon. Around this time you may also be asked to stop iron supplements, since iron can leave a residue that is hard to clean out.
The Day Before: Clear Liquids
The day before your colonoscopy, you will be on a clear liquid diet. Clear liquids are anything you can see through. Good choices include:
- Water
- Clear broth or bouillon
- Apple juice and white grape juice
- Plain coffee or tea with no milk or cream
- Clear sports drinks
- Plain gelatin and ice pops with no fruit pieces
Avoid anything red or purple, since the color can look like blood during the exam. Skip milk, juice with pulp, and solid food of any kind.
The Prep Solution
Your prep solution cleans out the colon. Most patients now use a split-dose prep, where you drink half the evening before and the other half early on the morning of the exam. Split dosing works better and is easier on your stomach. A few tips that help:
- Chill the solution in the fridge, since it goes down easier cold
- Drink it through a straw and follow each glass with a clear liquid you enjoy
- Stay near a bathroom once you start, as it usually begins working within an hour or two
- Use wipes and a barrier cream to stay comfortable
The goal is for your output to become clear or pale yellow liquid. If it is still cloudy by the time you finish, let our office know.
Medications to Adjust
Tell our office about all of your medications ahead of time. Blood thinners, diabetes medication, and iron supplements often need to be adjusted or paused. Never stop a prescribed medication on your own without checking with us first.
The Morning of Your Exam
Finish the second half of your prep within the window our office gives you, usually a few hours before your appointment. After that, stop all liquids as instructed. Because you will receive sedation, you must arrange for an adult to drive you home. You cannot drive, go to work, or sign important papers for the rest of the day.
What to Expect During and After
The exam usually takes 30 to 60 minutes. You will be sedated, so most people feel nothing and remember nothing. Afterward you may feel some gas or bloating, which passes quickly. I will share the initial findings before you leave, and if any tissue was removed, results from the lab usually take one to two weeks.
Common Prep Questions
If you feel sick to your stomach while drinking the prep, slow down and take a short break, then continue. If you vomit or simply cannot finish, call our office for guidance rather than skipping it. A complete prep is what keeps you from needing a repeat exam.
Talk to a Gastroenterologist in Mountainside, NJ
If your symptoms keep coming back or you are not sure what is causing them, Dr. Amber Khan can help. We see patients from across Union County and New Jersey.