Preparing for a colonoscopy

Scheduling your first colonoscopy is an important step in maintaining health for people over 50.  These screenings are the easiest and best way to prevent colon cancer by detecting polyps and removing them.  Even if you’re nervous, you’re making the right decision.

What is colonoscopy preparation?

Even if you’ve recently had a bowel movement, it’s likely that your colon still contains fecal matter that could keep your doctor from seeing your colon’s surface during the colonoscopy.  In order for the procedure to find and catch all colon polyps, it’s important to “flush out” the intestinal tract – a process called colonoscopy prep.  Preparation for a colonoscopy typically begins 1-2 days before the procedure, and will involve following a clear liquid diet as well as taking laxative medications.


Why is preparing for a colonoscopy important?

If the bowel prep fails to thoroughly empty the colon of fecal debris, your doctor may miss polyps or other lesions.  This may cause the colonoscopy to take longer, which increases the risk of complication.  You may need to postpone the procedure to another day, or even redo it in some cases.

Is there a “colonoscopy diet” I should follow before the procedure?

Yes. The day before your colonoscopy, your doctor will instruct you to stop eating solid foods and to only consume clear liquids. Examples of clear fluids include:

  • water
  • clear broth (beef or chicken)
  • coffee or tea without cream or milk
  • sports drinks
  • apple juice
  • clear sodas
  • juices without pulp such as apple juice, grape juice, cranberry juice
  • popsicles without fruit pieces or cream
  • clear gelatin without fruit pieces

Laxative medications: common options

Your doctor will recommend one of two common colonoscopy preparations: either a laxative solution or a sodium phosphate tablet. Both are designed to help the colon expel its contents as comfortably and non-invasively as possible. Plan to stay at home during this time, because preparation for a colonoscopy can mean numerous trips to the bathroom.

PEG cleansing solution (liquid – taken orally) Polyethylene glycol (PEG) An osmotic laxative, meaning that it pushes fluids through the bowel to force out waste.  Your doctor may also prescribe an anti-nausea drug.
Oral sodium phosphate (OSP) A saline laxative, which means that it draws water into the intestines to promote cleansing.  Drink plenty of fluids to prevent dehydration.

The colonoscopy prep prescribed and your doctor’s specific instructions will depend on the scheduled time of your procedure and any prior experience you may have with colonoscopies.  If one bowel preparation proved unsuccessful in the past, you will likely receive one different from before.

Whether it is your first colonoscopy or not, talking with your doctor about the prep that will best prepare you for the procedure may make the process less troublesome for you, and even reduce the risk of complication by effectively clearing your colon for examination.

Helpful tips:

  • Colonoscopy preparation may take up to a week because you may need to stop certain medications.  You will receive colonoscopy prep instructions far in advanced of the scheduled procedure—read them through the same day that you get them.
  • Some find the salty taste of PEG cleansing solutions unpalatable.  You can make it easier to drink by adding powdered drink mix, lemon (without pulp), or any other flavoring that is not dyed red, blue, or purple.  Using a straw can also make the liquid easier to swallow.
  • Although your diet may be restricted, remember that there are other liquids besides water that you can consume.  Diversity your clear fluids diet by having Jell-O (without fruit chunks), soft drinks, Italian ice, or fruit popsicles.


Have any other questions about preparing for your colonoscopy?  Feel free to contact us or call us at (480) 899-9800 with any questions or to set up a consultation.