Preparing for a colonoscopy? Read this first.


In this article:

  • Screening is a key element in preventing colorectal cancer, also known as colon cancer.

  • There are different types of screenings, including colonoscopies, which require preparation to clear the colon.

  • Prep can include avoiding high-fiber foods and taking anti-nausea medication.

  • Visit your physician at Swedish to learn more about whether you should schedule a colonoscopy.

March is National Colorectal Cancer Awareness Month — a good time to remember that screenings are a vital part of preventing this type of cancer.

Colorectal cancer is a term used to describe colon cancer, rectum cancer or both. According to the Centers for Disease Control and Prevention (CDC), colorectal cancer is the second leading cause of death for both men and women.

But it’s also one of the most preventable types of cancer. Regular screening is the key. Screening tests, such as a colonoscopy, help doctors find and remove small growths called polyps before they turn into cancer.

Who should be screened

If you’re 50 or older, being screened for colorectal cancer could be lifesaving. You may have a higher than average risk if you or a close relative had colorectal polyps or colorectal cancer. The risk also goes up if you have a condition such as Crohn’s disease or ulcerative colitis. Genes may also play a part in raising your risk of this type of cancer. If a family member has been diagnosed with colon cancer, it is recommended that you have a screening 10 years prior to their age at diagnosis. So, for example, if your father was diagnosed at age 52, plan to be screened at age 42.

If a family member has been diagnosed with colon cancer, it is recommended that you have a screening 10 years prior to their age at diagnosis.

There are different types of screening tests

One test isn’t “best” for everyone. They all have their pros and cons. Talk to your doctor about which one is better for you based on what you prefer, your health condition, whether you’ll go through with the test and whether the test you want is available. These tests include:

  • Stool tests, which include the guaiac-based fecal occult blood test (gFOBT) and the fecal immunochemical test (FIT)
  • Flexible sigmoidoscopy
  • CT colonography (virtual colonoscopy)

And there’s the big test: the colonoscopy.

Why a colonoscopy screening matters

If you’re squeamish about getting screened, keep this information in mind:

  • Treatment works best when colorectal cancer is found early.
  • Screening can find polyps and colorectal cancer even before symptoms appear.
  • About nine out of every 10 people whose colorectal cancers are found early and treated correctly are still alive five years later.

Read on for commonly asked questions about the colonoscopy procedure and how to prepare for it. Because the more you know, the better you’ll feel about making the wise choice to have this vital screening.

What happens during a colonoscopy?

While you’re sedated, your doctor will insert a thin, flexible tube with a tiny camera through the rectum and into the colon. The camera on the tube will show an image of the inside of your colon on a screen so the doctor can navigate effectively. 

Why is prep for a colonoscopy so important?

A successful colonoscopy hinges on a few things — chief among them is the preparation. Your system needs to be as clear as possible of solids and liquids to help the doctor see polyps or anything that could be concerning. And if the prep isn’t done well, the doctor may have to perform the exam again, which means another round of prep.

Good prep helps lead to an effective colonoscopy.  And if you do it right, you likely won’t have to repeat it for another five to 10 years.

The bottom line: Good prep helps lead to an effective colonoscopy.  And if you do it right, you likely won’t have to repeat it for another five to 10 years.

Tips on prepping for the prep

It’s normal to feel anxious about the colonoscopy prep. Here are a few tips that may help you feel more comfortable and set you up for a successful colon screening.

  • Get a head start. Once you get your prep instructions from the doctor, read them thoroughly at least a week before you have the colonoscopy so you can ask questions if needed. Buy the supplies you need so you’re not scrambling to find clear liquids, wipes, soft toilet paper and other items that will make prep day more comfortable. 
  • Don’t fill up on fiber. It may be tempting to do an early “clean out” using high-fiber foods but resist the urge. High-fiber foods can leave a residue in the colon and make it harder for the doctor to see polyps. A few days before the test, cut back on high-fiber foods such as beans nuts, whole grains, raw fruits and vegetables
  • Go for smaller meals. Try not to load up on food before you start the colonoscopy prep. It may be best to eat smaller meals a day or two before the prep to help you clear your bowels more easily and comfortably.

Tips for preparation day

  • Remember you have choices. One size doesn’t fit all when it comes to prep forms, flavors and liquid volumes. Work with your doctor to make sure you have the one that’s right for you. Newer preps are now lower in volume. For instance, you may be able to take a dose the night before and then the second one six hours before your colonoscopy. There are now even anti-nausea medicines to help the prep liquids go down more easily.
  • Plan to remain close to a bathroom. Avoid the stress of a sudden bowel movement once prep begins. Stay close to your bathroom, preferably in the comfort of your own home. And since you’ll be in the bathroom for a while, plan for that. Wear comfortable clothing and make sure you have ways to help you pass the time. These may include books, magazines, a tablet or a crossword puzzle. 

Preparing for a colonoscopy isn’t the most pleasant way to spend a day, but keep in mind why you’re doing it: Screening is key to preventing colon cancer.   

Find a doctor

If you have questions about colonoscopies, contact Primary Care or Gastroenterology at Swedish. We can accommodate both in-person and virtual visits.

Whether you require an in-person visit or want to consult a doctor virtually, you have options. Swedish Virtual Care connects you face-to-face with a nurse practitioner who can review your symptoms, provide instruction and follow up as needed. If you need to find a doctor, you can use our provider directory.

Join our Patient and Family Advisory Council.

Additional resources 

National Colorectal Cancer Awareness Month

Centers for Disease Control and Prevention — Colon Cancer

American Cancer Society — Colorectal Cancer

Colonoscopy — It’s not so scary!

Why dietary fiber reduces the risk of disease

This information is not intended as a substitute for professional medical care. Always follow your health care professional's instructions.

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About the Author

The Swedish Digestive Health Team is committed to helping you navigate the complexities of the organs and their many functions to find the right treatment for your unique digestive condition.

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