News center
Our goal is to continuously improve our techniques and quality to meet your needs.

How to Prep for Your First Colonoscopy, According to Experts

Mar 29, 2023


Supported by

Millions of people get colonoscopies each year to screen for colorectal cancer. Experts share strategies that can make the experience as smooth as possible.

Send any friend a story

As a subscriber, you have 10 gift articles to give each month. Anyone can read what you share.

By Trisha Pasricha

Dr. Trisha Pasricha is a gastroenterologist at Massachusetts General Hospital.

When patients come to me for their first colonoscopies, the first thing I usually say is, "Congratulations!" As a gastroenterologist, I applaud them for doing something important for their health and share in their joy that the hardest part of the colonoscopy process — the preparation — is behind them.

Whether a colonoscopy is in your future because your doctor would like to investigate certain symptoms like chronic diarrhea or rectal bleeding, or you’re being screened for colorectal cancer (which is now recommended for most people to begin at age 45), you’ll need to prepare.

I spoke with other experts who shared tips on how to make the experience smoother.

If you’ve heard about colonoscopies from family members or friends, you may be surprised by how much the preparation and procedure have changed from prior generations.

You’ll still have to cleanse your colon beforehand, but there are many new laxative options — in liquid, powder and pill form — that won't require you to chug more than a dozen cups of salty formula in one sitting. The Suprep Bowel Prep Kit, for example, requires drinking just two cups of liquid laxative — once in the evening before your procedure, and once the morning of. And Sutab, a recently approved pill-based option that involves swallowing two doses of 12 tablets, is enticing for many people who wish to avoid liquid- or powder-based laxatives (which may taste unpleasant).

The colonoscopy procedure itself has also modernized. There are now safer ways to puff up the colon to hunt for precancerous growths, better cameras to aid in the hunt, and more sophisticated techniques for removing abnormal tissue.

In fact, colonoscopies have become so much safer and more comfortable for my patients that it's common for them to wake up after the procedure and ask, "Is that it?" or "When are we starting?"

Colonoscopies, like all procedures, can come with certain serious — yet rare — risks. And your preparation instructions will vary depending on your medical needs and the specific laxatives you are prescribed, so it's important to review everything with your physician in advance.

Starting the day before your colonoscopy, you will begin the famous bowel preparation. This involves starting a clear liquid diet for a day before the procedure, and taking laxatives that cleanse your colon. Laxatives are split into two doses — one taken the night before the procedure and another taken the morning of. A poor prep is the reason up to a quarter of colonoscopies cannot be completed.

"A very substantial portion of precancerous lesions in the colon are quite subtle," said Dr. Douglas Rex, a gastroenterologist and professor of medicine at Indiana University School of Medicine. "In order to see those well, the colon has to be clean."

Three days before your colonoscopy. Cut out high-fiber foods like nuts, seeds, whole wheat bread and raw vegetables, as they take longer to pass through your digestive tract and can make it harder for your physician to see inside your colon.

Some people think of the few days before their liquid diet as their last chance to eat well, but overindulging can set you back — the more you eat, the more your body will need to expel.

You’ll also want to make sure you have someone scheduled to pick you up after the procedure (you won't be allowed to drive because of the sedation).

The day before your colonoscopy. When you wake up the day before your procedure, you’ll start a strict clear liquid diet (which can also include certain foods). Water, chicken broth and apple juice are allowed, as are foods like pulp-free Popsicles or even Jell-O, as long as everything is clear or light in color. (Red Jell-O, for instance, can be mistaken for blood.) Black coffee and tea also count as clear liquids, "so your mornings don't have to be totally ruined," said Dr. Audrey Calderwood, director of The Comprehensive Gastroenterology Center at Dartmouth Hitchcock Medical Center.

Usually by the afternoon or evening, you’ll be instructed to take the first dose of your prep, so plan for a cozy night in and stay close to the bathroom.

If your prep needs to be mixed with another liquid, that liquid must be clear, but don't be afraid to get creative with the flavor combinations. Ginger ale, fruit juice, sports drinks or tea can make the solution more palatable — and you can even try a savory version by mixing in the flavor packet from ramen noodles.

Some people find the taste of certain preps unpleasant, so if you get queasy easily, ask your physician in advance for anti-nausea medication. Drinking your prep solution with a straw can help limit how much of it you smell; sucking on mints or menthol lozenges between sips can also help blunt any bad tastes. Chilling the prep in the refrigerator can also help with the taste; just avoid using ice if you aren't going to drink it quickly, Dr. Calderwood said. When the ice melts, it will dilute the mixture, resulting in more volume to drink.

And whatever you do, don't drink alcohol the day before your procedure. While it technically might be a clear liquid, alcohol can cause dehydration and interfere with sedation, which can make for a dangerous combination.

The purge will happen anywhere from a few minutes to a few hours after starting your laxative, so stock up beforehand on gentle toilet paper or wet wipes with soothing witch hazel or aloe vera. (Just don't flush your wet wipes, even if they say "flushable" on their packaging, because they can harm the environment and clog pipes.)

The morning of your colonoscopy. Several hours before your procedure, you will likely be instructed to take the second dose of the prep. You will also need to stop drinking all liquids at least two to four hours before your scheduled procedure, as directed by your physician.

By this point, your stools should be liquid and see-through. If they’re not, be honest with your doctor. "The last thing you want is to put in all this effort, take time off and then the job doesn't get done," Dr. Rex said. It's normal for patients who have certain conditions (like chronic constipation) or who are on certain medications (like opioids) to take longer to prep adequately, so be sure to review your medical history with your physician before getting started. Sometimes, simply taking the bowel prep for one more day will solve the problem.

Don't forget to pack a snack for the car ride home — you’re going to be hungry and may want more than the salt-free crackers the nurses might offer you in the recovery area.

It's very important that you follow your doctor's instructions carefully in advance of your procedure. If you don't, you’ll have to go through the process again much sooner — within one year as opposed to up to 10 years, as is recommended for most people with a normal examination and a clean prep.

"I think everyone would rather just do a ‘one-and-done’ and do it well, than have to come back again so quickly," Dr. Calderwood said. "Often, we won't know how bad the prep is until after the patient has already been sedated and we take a look."

For many people, Dr. Calderwood said, the psychological aspects of preparing for a colonoscopy are more challenging than the physical ones. You’ll have to contend with (a lot of) diarrhea, a lack of solid food for 24 hours and sedation for a procedure — all of which can feel overwhelming.

"It's almost like gearing yourself up to run a marathon," Dr. Calderwood said. But just remember, it's not an insurmountable task. "Lots of people before you have done it and are doing it every day," she said.

Try to cut yourself some slack and feel good about why you’re doing this procedure, even when it's hard. After all, getting a colonoscopy is an act of self-care that can give you and your loved ones peace of mind once it's over.

"Any unpleasantness before the colonoscopy is going to be finite," Dr. Calderwood said. "And then in all likelihood, you aren't going to have to think about it again for several years."

Dr. Trisha Pasricha is a gastroenterologist at Massachusetts General Hospital and a contributor to The New York Times.


Send any friend a story 10 gift articles Three days before your colonoscopy. The day before your colonoscopy. The morning of your colonoscopy