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Understanding Bowel Prep

Bowel prep is a key part in getting ready for some procedures, like a colonoscopy. This sheet will help you better understand it. If you have any questions or concerns, talk with your healthcare provider. They are here to help.

What is bowel prep?

Before you have certain procedures, such as a colonoscopy, you need to clean out your colon. This process is called bowel preparation, or bowel prep. You may be feeling anxious about doing it. That’s OK. Try focusing on this: When done correctly, bowel prep helps your healthcare provider better see the inside of your colon. Your provider can then more easily find early signs of cancer, such as polyps. These small growths may become cancer over time. Bowel prep can also help prevent complications after some surgeries.

For the bowel prep, you will be given a strong laxative. This medicine may be in liquid or pill form. You will usually start taking this medicine the day before your procedure. After taking the laxative, you will have watery poop, or diarrhea. Over time, your poop will get more and more watery and turn a yellow or clear color as the medicine cleans out your colon.

Before some procedures, your healthcare provider may instruct you to use an enema. This treatment involves injecting fluid into the rectum to help cleanse or stimulate the emptying of the bowel. Talk with your provider if you have questions about doing an enema.

What to expect

Before bowel prep

There are many different types of bowel prep medicine. You and your healthcare provider will choose the best one for you. This choice will be based on your age, your health, other medicines you take, the cost to you, and your preferences.

To help choose the best bowel prep method for you:

  • Tell your healthcare provider what medicines you take. Include both prescription and over-the-counter medicines. Also include vitamins, herbs, and supplements. Your provider may tell you to stop taking some medicines, like blood thinners, before you start the bowel prep.

  • Tell your provider about any allergies, infections, or conditions you have, such as diabetes, heart failure, or liver disease. These may affect the safety and effectiveness of the bowel prep.

  • Tell your provider if you think you may have trouble drinking large amounts of fluid over a short period of time.

  • Read all your bowel prep instructions before the day you start the bowel prep. You may need to plan or buy certain things. Or you may have questions to ask your provider.

During bowel prep

Your healthcare provider will tell you exactly how to do the bowel prep. If something seems unclear, ask questions. Your provider is here to help.

Starting the day before your procedure, you will need to be on a clear liquid diet. That means not eating any solid foods until after your test. Drinking large amounts of liquid with the bowel prep medicine helps clean out your colon. It also prevents dehydration. During this time, you can have:

  • Water

  • Coffee and tea without milk or creamer

  • Clear broth or bouillon

  • Gelatin snacks without any fruit or toppings

  • Ginger ale

  • Lemonade without any pulp

  • Clear fruit juice like white grape or apple

  • Some sports or hydration drinks

Stay away from orange juice and dairy products, like milk. These are not clear liquids. Also don’t have any red- or purple-colored drinks or gelatin. These can affect the quality of a colonoscopy.

The afternoon or evening before your procedure, you will start taking the bowel prep medicine. You will take it over a few hours. For most bowel preps, whether liquids or pills, you will likely be told to take half of it in the evening and the rest in the morning about 5 hours before your appointment. This is called split-dosing and helps clean the bowel better.

During this time, stay close to a bathroom. You will start to have diarrhea. You may also have mild nausea, bloating, or stomach pain. Tell your healthcare provider if these symptoms last a long time or get worse.

What to keep in mind

These tips may help with bowel prep:

  • Take the bowel prep medicine as directed. It’s the best way to make sure your procedure will be a success.

  • Tell your healthcare provider right away if you are not able to finish the bowel prep. Also tell your provider if your poop has not turned a yellow or clear color after finishing the prep. They may be able to help. In some cases, your procedure may need to be rescheduled.

  • To improve the taste of liquid bowel prep medicine, add the flavor packet if included. You can also try chilling it or using a straw to drink it. Sucking on lemon wedges or menthol candies after taking the medicine may help, too.

  • Follow all instructions you are given about when to stop eating and drinking. You may be able to have sips of water until 2 hours before your procedure. But you must check with your provider about your specific instructions.

Online Medical Reviewer: Jen Lehrer MD
Online Medical Reviewer: Marianne Fraser MSN RN
Date Last Reviewed: 3/1/2024
© 2000-2024 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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