Bowel Prep and Colonoscopy Frequently Asked Questions (FAQ)

bowel prep and colonoscopy

Frequently asked questions about bowel preparation and colonoscopy like what is bowel prep? What is low fiber diet? What is clear liquid diet? Should I stop aspirin before colonoscopy? Get answers to these frequently asked questions (FAQ) and others at BOWELPREPGUIDE.COM/FAQ.

What is bowel preparation?

Bowel preparation is the process of preparing your bowel for an effective diagnostic or therapeutic medical procedure such as colonoscopy or surgical procedure such as colon resection.

Why is adequate bowel preparation important?

Adequate bowel preparation is the key to a successful colonoscopy. It allows your provider to see the mucosal lining of your colon.

For the individual, inadequate bowel prep means aborted procedures, repeat procedures, reduced detection of polyps and cancer, increased risk for complications, lost co-pays and cost of transportation, lost day at work and wages, lost productivity for patient and accompanying adult.

To the healthcare system, inadequate bowel prep means longer procedure time and increased use of resources.

For the society, inadequate bowel prep means increased healthcare cost, lost productivity and opportunity cost, and increased morbidity and mortality from colorectal cancer.

To learn more about the consequences of inadequate bowel prep, read The hidden costs of an inadequate bowel preparation for colonoscopy.

What are the bowel preparation agents approved by the FDA?

Colyte (Alaven), GoLYTELY (Braintree), NuLYTELY (Braintree), TriLyte (Alaven), HalfLytely (Braintree), MoviPrep (Salix), SUPREP (Braintree), OsmoPrep (Salix), Visicol (Salix), Prepopik (Ferring), CLENPIQ (Ferring), Plenvu (Salix). Even though, MiraLax is not FDA-approved for bowel preparation, it is approved for constipation and is widely used for bowel preparation.

How do I use Golytely, Nulytely, Trilyte or Colyte for colonoscopy bowel preparation?

Click HERE.

How do I use Suprep for colonoscopy bowel preparation?

Click HERE.

How do I use MoviPrep for colonoscopy bowel preparation?

Click HERE.

How do I use Prepopik for colonoscopy bowel preparation?

Click HERE.

How do I use Miralax and Gatorade for colonoscopy bowel preparation?

Click HERE.

How do I use Osmoprep for colonoscopy bowel preparation?

Click HERE.

How do I use CLENPIQ for colonoscopy bowel preparation?

Click HERE.

How do I use Plenvu for colonoscopy bowel preparation?

Click HERE.

How do I follow the 2 day bowel prep?

Click HERE.

Can I use my bowel cleansing agent only on the day of the colonoscopy? The same day bowel prep. 

Click HERE. 

What is the best bowel preparation agent?

The best bowel preparation agent is the one you can take. There are many bowel prep agents in the market. Often, your medical history and health insurance will dictate the type of bowel prep agent you can have. Regardless of the type you are given, a split regimen is superior to a night before regimen.

What are the 3 different ways to take bowel cleansing agents for colonoscopy?

Read HERE.

How do I follow the split dose regimen for bowel preparation?

Take half the total dose of your purgative the night before your colonoscopy. This is usually between 5-8 PM. Make sure to take plenty of fluids throughout the day in addition to the fluids used for your bowel preparation. You need to stay hydrated throughout the process.

The second half of your prep should be started 4-5 hours before the time of your colonoscopy. Be sure to finish it at least 2 hours before your procedure time.

Why can’t I take all the bowel prep the day before my colonoscopy?

Multiple studies show that splitting the bowel cleansing agent into two 2 doses clean the colon better and is better tolerated .

I have an early morning appointment. Do I have to wake up in the middle of the night to take the 2nd half of the prep?

Yes. You should plan to take the 2nd half 4-5hrs before your scheduled colonoscopy. Even without eating, your intestine produce stool material. The 2nd half acts as a rinse to clean the colon out.

More Frequently Asked Questions

What food can I eat before colonoscopy?

Just because you’re scheduled for colonoscopy, does not mean you have to starve. You can eat before your colonoscopy.  The kind of food you eat depends on your health problems, previous cleanliness levels during colonoscopy and your doctor’s preference. Some people are easier to clean out than others. Read Predictors of Inadequate Bowel Preparation. There are 2 main diets before colonoscopy. The clear liquid diet and the low fiber diet. The low fiber diet is also called the low residue diet. Please, follow the specific diet recommended by your doctor. To read more, click HERE.

What is clear liquid diet?

Clear liquid diet excludes red and purple colored substances. Alcohol is also not allowed. Examples of clear liquid diet include water, tea, plain coffee, lemonade from powdered mix, carbonated beverages and soda, clear juices such as apple and white grape, plain or flavored gelatin, sports drinks such as Gatorade® , All-Sports®, Powerade®; sorbet, popsicles, honey, sugar, hard candy, fat-free broth, bouillon or consommé.

What is low residue (or low fiber) diet?

Residue refers to undigested food or fibers that make up part of the stool. A low residue diet reduces the frequency and volume of stool while prolonging the time it takes food to travel the intestine. You should avoid the following food items: whole wheat breads, cereals, crackers and rolls; whole wheat pasta, brown or wild rice; any item with nuts, seeds and fruits; buckwheat, granola, cornbread, pumpernickel bread; tough meat and meat items with skin; raw fruits, prunes and prune juice, berries, raisins and dried fruits; raw or partially cooked vegetables. You should also avoid milk and milk products.

If you are on a low residue diet, you may be allowed to have white bread, rolls and biscuits; white rice or noodles; plain crackers, potato rolls, skinless cooked potato; skinless chicken, skinless turkey, fish and other sea food; canned fruits without seeds or skin; eggs; vanilla wafers.

What are the possible side effects of bowel prep agents?

Though rare, the following adverse reactions have been reported. Abdominal fullness and cramping, nausea, vomiting, electrolyte abnormalities, cardiac arrhythmias, seizures, and renal impairment. If you have nausea or start vomiting, stop drinking for 30-45 minutes until the symptoms subside, then you may resume. Some people require anti-nausea medications. You will have diarrhea so stay near a toilet. Use a soft toilet tissue. For anorectal irritation or discomfort, use baby wipes, hydrocortisone cream or hemorrhoidal agents. You may call your provider at anytime if you feel very uncomfortable or sick.  Read Adverse Events (Side Effects) of Bowel Preparation Agents and How to Handle Them.

Can I tell if I my bowel preparation is adequate for colonoscopy?

Your rectal effluent or stool after finishing your bowel prep agent can act as a guide. Your stool should be clear, yellow, light and liquid. The presence of dark particles or thick brown or black stool means you are not ready for colonoscopy. If your stool is not clear after taking your entire bowel prep agent, you may need additional prep agent. Read How to Tell If Your Bowel is Clean Prior to Colonoscopy.

What medications should I discuss with my provider before bowel preparation?

In general, your provider should be aware of all your medications before your colonoscopy. You should STOP taking fiber supplements and fish oil 2-3 days before your scheduled colonoscopy. If you take any of these medications, discuss with your provider one week before your scheduled colonoscopy. Some of these medications may need to be stopped or their dosages adjusted prior to your colonoscopy and during your bowel preparation.

  1. Anti-inflammatory medications like Ibuprofen, Advil, Motrin, Aleve, Naprosyn, and Naproxen.
  2. Antiplatelet medications like aspirin, Clopidrogel (Plavix), Ticlopidine (Ticlid), Prasugrel (Effient), Ticagrelor (Brillinta), Dipyridamole (Persantine), Aggrenox (dipyridamole plus aspirin), Abciximab (ReoPro)
  3. Anticoagulants like Coumadin or Warfarin, Rivaroxaban (Xarelto), Apixaban (Eliquis), Dabigatran (Pradaxa), Bivalirudin (Angiomax), Argatroban, Enoxaprin (Lovenox), Dalteparin (Fragmin), Tinzaparin (Innoprin), Fondaparinux (Arixtra).
  4. Hypoglycemic agents like insulin, metformin, glyburide, glipizide, glimepiride, acarbose, miglitol, voglibose, Pioglitazone (Actos), Rosiglitazone (Avandia), Exenatide (Byetta), Liraglutide (Victoza), sitagliptin (Januvia).

This list is by no means exhaustive. Tell your provider all the medications you take including over the counter and herbal supplements.

I have diabetes mellitus. How do I prepare for colonoscopy? 

Click HERE. 

More Frequently Asked Questions

How can I make my bowel preparation agent (laxative) taste better OR less awful?

Bowel preparation agents often taste bad. Generally, sulfate containing formulas (e.g. GoLYTELY, and Colyte) are less palatable compared to non-sulfate containing formulas (e.g. NuLYTELY, and TriLyte). To improve their taste, some prep agents come in flavored packs e.g. NuLYTELY (flavors: cheery, lemon-lime, orange, pineapple), TriLyte (flavors: cherry, citrus-berry, lemon-lime, orange, pineapple), and HalfLytely (flavor: lemon-lime).

To improve taste, the following have been suggested:

  1. Chill the bowel cleansing liquid by putting it in a fridge or ice bucket.
  2. Use straw. Sipping is better than gulping.
  3. Add flavor. You can add lemon juice, lemon slices or sugar free flavor enhancers like Crystal Light®.
  4. Sugar free menthol-candy. Suck on menthol candy (e.g. Halls menthol candy) during ingestion of the bowel prep solution.

For other colonoscopy tips, read 10 Tips for Making Colonoscopy Preparation More Tolerable.

What can I do to make my bowel preparation better? My last colonoscopy was a “poor prep”

The solution to a “poor prep” resides in the reason for the poor prep. Ask yourself these questions?

  1. Did I follow the instructions? If not, why? Was it confusing? Is it in a language or format you understand? You should receive bowel prep instructions in the language you understand. You may need visual aids in brochures to improve your understanding. Some may benefit from an instructional video on bowel prep. If you forgot your instructions, you may benefit from reminders such as stickers posted on easily seen items, use of a person to remind you or apps that can be downloaded on smart phones and tablets.
  2. Do you have any risk factor for inadequate bowel preparation? These include medical conditions such as obesity, diabetes mellitus, chronic constipation, use of constipating medications such as opioid narcotics, psychotropic agents, prior resection of the colon, stroke, dementia, cirrhosis, prior abdominal surgeries such as hysterectomy and appendectomy, and history of prior inadequate bowel prep. If the answer is yes. You may need additional intervention such as being on a low fiber diet for 72 hours prior to your colonoscopy, being on a clear liquid diet for 24-48 hrs prior to your colonoscopy, use of laxative adjuncts such as bisacodyl or magnesium citrate in addition to your bowel prep agent. In addition, you may also require large volume agents such as GoLYTELY instead of low volume agents such as MoviPrep and Prepopik.

Why should I avoid red or purple colored drinks and food?

These food items may resemble blood in the colon and confuse your provider.

Why should I avoid seeds and nuts prior to colonoscopy?

These foods are hard to digest and may remain in your colon. They are hard to wash out of the colon and may clog the instruments used for colonoscopy (scope).

Why can’t I drive or go to work after my colonoscopy?

Sedation during colonoscopy impairs judgment, memory and reflexes. You should have someone to take you home after your colonoscopy. You may return to work or drive the day after your colonoscopy.

I already have diarrhea before starting my bowel prep, do I still need to do bowel prep?

Yes. You still need bowel preparation prior to your colonoscopy. Your intestine continue to produce waste materials even with diarrhea. It is important to have a clean colon during your colonoscopy.

My stool is watery and clear, do I still need to drink the entire bowel prep     solution?

Yes.  Drinking your entire prep solution ensures complete cleaning of your colon.

Can I do bowel prep and colonoscopy while I am having my period (menstruation)?

Yes. Bowel preparation and colonoscopy are safe during menstruation.


I have drunk a lot of prep solution and haven’t gone to the bathroom… Do I continue? How long does it take to work?

Yes, continue drinking. You will eventually have a bowel movement. Time to bowel movement varies. Some people have bowel movement within minutes while others take hours. Make sure you drink the entire bowel prep solution. If you still have solid stools or brown stool or stool with particles after finishing your bowel prep, contact your physician.

Do I need to stop aspirin before a colonoscopy?

No. Colonoscopy while on aspirin is safe. Patients that take aspirin for heart and blood vessel disease, can continue to do so before and after colonoscopy. Ask your doctor if he wants you to stop aspirin for other reasons.

Do I need to stop non-steroidal anti-inflammatory drugs (NSAIDS) like naproxen, ibuprofen, celebrex before a colonoscopy?

No. Colonoscopy can be safely performed while on these medications. Your doctor may want you to stop these medications for other reasons.

Do I need to stop plavix before a colonoscopy?

No. Depending on the planned intervention during colonoscopy and the reason for plavix use, plavix may need to be stopped for a few days prior to colonoscopy. Discuss use of plavix before colonoscopy with your doctor.

More Frequently Asked Questions

Is it okay to have sex a day before or after a colonoscopy?

Yes, as long as your are doing fine.

Can Colonoscopy cause sneezing and runny nose?

Yes. Read THIS. 

What should I wear on the day of my colonoscopy procedure?

You should wear comfortable clothes you can easily put off and on. You will be given a gown to wear during the colonoscopy.

Will I be asleep during my colonoscopy?

It depends. Colonoscopy can be safely performed without sedation. You can watch your colonoscopy alongside the physician on the video monitor. Most people elect to have sedation. Sedation can be light, moderate or deep. You should be completely asleep with deep sedation. Moderate sedation is the most common sedation used in colonoscopy. Most people are asleep with moderate sedation but can be aroused if necessary.

Will I feel pain during colonoscopy biopsy or polyp removal?

No. Rarely, a post-polypectomy syndrome can occur causing abdominal pain after colonoscopy. Most of the discomfort during and after colonoscopy come from the air (or carbon dioxide) used to distend the colon for proper inspection.

How can I spot a complication after colonoscopy?

To identify complications after colonoscopy and what to do, click HERE.

What causes diarrhea or constipation after a colonoscopy?

Read HERE.

Is YouTube reliable as a source of information on bowel preparation?

In one study, about sixty percent of YouTube videos were considered low-content videos. There was no association between the number of views, number of comments, thumbs up, thumbs down or engagement score, and videos deemed high-content.    Read YouTube™ as a Source of Instructional Videos on Bowel Preparation: a Content Analysis.

I have an artificial joint. Do I need antibiotic prior to colonoscopy?

No. For more information, click HERE.

I have an artificial heart valve. Do I need antibiotic prior to colonoscopy?

No. For more information, click HERE.

I have kidney failure. How do I prepare for colonoscopy?

Click HERE. 

I have heart failure. How do I prepare for colonoscopy?

Click HERE. 

I have seizures. How do I prepare for colonoscopy? 

Click HERE. 

Can I brush my teeth on the day of colonoscopy?

Yes. Brushing your teeth will not affect your bowel prep or colonoscopy.

Can I chew gum or suck candy during bowel prep?

Yes. In fact multiples studies suggest that chewing gum or sucking on Hall’s cough drops while you drink your bowel cleansing agents can improve the taste of the bowel cleansing agents.

More Frequently Asked Questions

What is a colon polyp?

For information on colon polyps, click HERE.

I just received my pathology report. Where can I get help understanding my report?

For more information about different types of colon polyps and understanding your pathology report, click HERE.

I have more questions about colonoscopy like How do I shop for a colonoscopy? When should I get a screening colonoscopy? How often should I get a colonoscopy? Where is colonoscopy performed? Who performs a colonoscopy? Will I feel pain during colonoscopy? Will my insurance cover my colonoscopy? What is the cost of colonoscopy?

Read All Your Colonoscopy Questions Answered

How do I hack my colonoscopy?

Click HERE.

What is the difference between a screening colonoscopy and a diagnostic colonoscopy? 

A screening colonoscopy is a preventative test to screen individuals without any symptoms or signs for colorectal polyps and cancer. A diagnostic colonoscopy is done for individuals with symptoms or signs such as diarrhea, blood in the stool, abdominal pain, anemia.

How do I code or bill for colonoscopy?

Read my colonoscopy bill: the true cost of colonoscopy. For more information, click HERE and HERE.

Is there a puzzle about colon cancer awareness month? 

Yes. Read colon cancer awareness puzzle.

What are the colonoscopy videos I need to see before my test? 

There are three colonoscopy videos you need to see before your test. See them HERE.