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How to Prepare for a Colonoscopy
30 October 2026 | General Information
Most people who dread a colonoscopy aren't dreading the procedure. The procedure itself is quick, and you're usually asleep and sedated for it. The part people talk about is the prep the day before. Once you know what to expect, it's very manageable, and a little planning makes the whole process smoother.
This article is a general overview to how colonoscopy prep works. Your doctor will give you specific instructions based on the exact prep product prescribed for you, and those instructions are the ones to follow. If anything below differs from what your care team told you, go with theirs.
Why the Prep Matters
The prep clears out your colon so your doctor can see the lining clearly. A clean colon means a more accurate exam and a better chance of catching small polyps before they become a problem. If the procedure preparation isn't thorough, your doctor may not be able to see everything, and the procedure may have to be repeated. That's why the instructions are so specific. Finishing the prep completely, even when you feel like you're already empty, is what makes the exam work.
About a Week Ahead
A few things are easier to handle before prep day arrives.
Arrange a ride home
Since you'll be sedated, you cannot drive yourself afterward. Ask a friend or family member to pick you up, or plan for a ride service if your center allows it. Ride share services are permitted if you have someone with you
Pick up your prescription
Your prescription is usually sent to your pharmacy electronically ahead of time. Grab it early so you're not scrambling the day before.
Talk to your doctor about your medications
Some medications need to be paused or adjusted before a colonoscopy, including blood thinners, certain diabetes medications, and iron supplements. Don't stop anything on your own. Ask your care team which of your regular medications to continue and which to hold.
Shift to a low-fiber diet in the days leading up to the procedure
Fiber takes longer to clear, so easing off it early helps the prep work better when the time comes.
Foods to cut back on include:
- Nuts and seeds
- Popcorn
- Raw vegetables
- Fruit with skins
- Whole grains
- Beans.
Easier-to-digest choices like white bread, white rice, eggs, plain chicken, and well-cooked vegetables without skins tend to sit better. This is also a good time to stock up on the clear liquids you'll want for the next day so they're ready and, where it helps, chilled.
The Day Before
Clear liquids only
The day before means no solid food. Clear liquids are anything you can see through. Water, clear broth, apple or white grape juice, plain coffee or tea without milk or creamer, clear sports drinks, and plain gelatin all count. Popsicles without fruit chunks are fine too.
Skip anything red, purple, or blue
Dyes in those colors can tint the colon and look like blood during the exam. Choose lighter colors like yellow, orange, and clear instead. Avoid alcohol while you're prepping, since it works against staying hydrated.
At the time your instructions specify, you'll begin drinking your bowel prep. Expect things to get moving within an hour or two, and plan to stay close to a bathroom for the next several hours. Having soft toilet paper or wipes and something to read or watch nearby makes the time more comfortable.
Why You Drink It in Two Parts
If your instructions have you drink half the prep the evening before and the other half early the next morning, that's called split-dosing, and it's now the recommended approach. Splitting the dose cleans the colon more effectively and tends to be easier on your stomach than drinking it all at once. It may seem odd to wake up early to finish it, but that second dose is a big part of what makes the exam clean, so it's worth following exactly as recommended (even stools are clear after the first half.) Getting through the prep more comfortably
The prep solution isn't anyone's favorite drink, but a few tricks help:
- Chill it in the fridge ahead of time, since it goes down easier cold.
- Drink each glass steadily rather than sipping slowly, and use a straw placed toward the back of your tongue to bypass some of the taste.
- Sucking on a lemon wedge or a hard candy between glasses helps too, as long as it isn't red or purple.
- If you start to feel queasy, pause for about 30 minutes, then resume slowly.
How to Know It Is Working
As the prep does its job, your stools will become more and more liquid and lighter in color. When you're finished, what's coming out should look like clear or yellowish liquid, similar to urine. That's the sign your colon is clean and ready. If you've finished the full prep and things still look solid or dark, call your doctor's office for guidance.
The Morning of Your Procedure
Follow your instructions on when to stop drinking all clear liquids. Many centers ask you to stop a few hours before your arrival time, so double-check yours. Wear something comfortable, leave jewelry and valuables at home, and bring your ID, insurance card, and a list of your medications. Remember that your ride needs to be available, since you won't be cleared to drive.
When to Call Your Doctor
Reach out to your doctor's office if you can't keep the prep down, if you have severe pain or bloating, if there's no bowel activity several hours after starting, or if you're unsure whether your colon is clean enough. They would much rather answer a question the night before than have you reschedule.
Colonoscopy prep asks for one focused day, and it's the small price for an exam that can catch problems early or rule them out entirely. If you have a colonoscopy coming up with Charlotte Gastro and questions about your prep, our team is glad to walk you through it.