Bowel cleansing medicines

Key points about bowel cleansing medicines

  • Bowel cleansing medicines are used before a bowel examination or procedure such as a colonoscopy or bowel surgery.
  • They're used to ensure the bowel is free of poos (bowel motions/stools).
  • Find out how to take them safely and possible side effects.
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Medicines for bowel cleansing are used before a bowel examination or procedure such as a colonoscopy or bowel surgery. They're used to make sure your bowel is free of solid contents (poos). Your bowel needs to be empty so the lining can be clearly seen during the procedure. 

There are a variety of medicines used for bowel cleansing, but they're all laxatives that will cause you to pass bowel motions (poos) very often. Some of the medicines come as sachets of powder, which need to be dissolved in water. Your doctor will give you written instructions of the bowel preparation schedule best for you.

Examples of medicines for bowel cleansing
  • Glycoprep
  • Glycoprep-C 
  • Moviprep
  • Klean-Prep
  • Bisacodyl
  • Phospho-Soda
  • Fleet Phospho-Soda
  • Picoprep
  • Picosalax
  • Plenvu
  • Prepkit-C

Medicines for bowel cleansing aren't treatments for constipation or other purposes such as detoxification.

Your bowel preparation instructions will have information on:

  • which bowel cleansing medicines to use
  • when to start taking them
  • how long to use them for, and
  • any other special instructions.

Together with the medicines for bowel cleansing you may be asked to eat foods and drink liquids that are easier for your gut to digest, to help empty the bowel. 

Preparing your bowel in the right way is very important for your examination to be successful. Talk to your healthcare provider if you're not sure about how to prepare and take your bowel cleansing medications, when to take them or have any other questions.

Taking bowel cleansing medicine is not always pleasant. Here are a few tips to help you.

  • Be prepared: Make sure you read the instructions ahead of time so that you can ask your healthcare provider questions about things you are unsure of.  
  • Improve the taste: If you don't like the taste, try keeping the solution chilled in the fridge. It may be helpful to drink the mixture through a straw or try adding some flavouring, as long as what you are adding is clear in colour.
  • Keep yourself hydrated: It's important to drink clear fluids while you are using bowel cleansing medicines, to help clear your bowel and to prevent dehydration. Examples of clear fluids are water, clear salty fluids (eg,. strained chicken noodle soup), clear broth, clear fruit juices (apple, pear, and grape), plain jelly, black tea or coffee (no milk), sports drinks, carbonated beverages, clear fruit cordials (clear lemon/lime). Red or purple colourings must be avoided. 
  • Stay close to a toilet: This is because bowel cleansing medicines cause multiple and sometimes sudden bowel motions, so it's important you stay close to a toilet. You may feel the need to poo as soon as 30 minutes after you first start taking the medicine. 
  • Sore bottom: Your bottom may get sore from wiping after multiple bowel motions. You can apply Vaseline or another barrier cream to your bottom before and after going to the toilet. Using wet wipes (baby wipes) instead of toilet paper may help but dispose of these in your rubbish bin, don't flush wipes down the toilet.
  • Ask about your regular medicines: If you are taking regular medicines for other conditions, ask your healthcare provider about whether you need to continue with these or not. Some medicines need to be stopped, but others may need to be continued until you have the procedure. 

  • Do you have Crohn's disease or ulcerative colitis?
  • Do you have kidney problems?
  • Do you have heart problems?
  • Do you have diabetes?

If you have any of these it’s important that you tell your healthcare provider before you start bowel cleansing medicine. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

Like all medicines, bowel cleansing medicines can cause side effects although not everyone gets them. Common side effects include nausea (feeling sick), vomiting (being sick), stomach pain and stomach bloating.

You can lessen any stomach pain you have by trying to drink smaller amounts of the bowel cleansing medicine over a longer period of time. Ask your healthcare provider what to do if you get any side effects that bother you.

The links below provide more information about each of the bowel preparation medicines listed.

Each hospital will have its own bowel preparation instructions. It's important to only follow the instructions given to you by your healthcare provider.


  1. Bowel cleansing preparations(external link) New Zealand Formulary

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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Stephanie Yee, Pharmacist

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