Bowel cleansing medicines

Bowel cleansing medicines are used before a bowel examination or surgical procedure such as colonoscopy or bowel surgery. Find out how to take them safely and possible side effects.

Medicines for bowel cleansing are used before a bowel examination or surgical procedure such as colonoscopy or bowel surgery. They are used to ensure the bowel is free of solid contents (poos). For example, if you are having a colonoscopy, your bowel needs to be empty so the lining can be clearly seen during the procedure. Read more about colonoscopy.

Medicines for bowel cleansing are not treatments for constipation or other purposes such as detoxification.

Examples of medicines for bowel cleansing

There are a variety of medicines used for bowel cleansing. These will cause you to pass 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
  • Prepkit-C

Bowel preparation schedule

Your bowel preparation schedule will have information on which bowel cleansing medicines to use, when to start taking it, how long to use it for and any other special instructions. For example, you may be asked to reduce the fibre in your diet, in the days leading up to the procedure.  

Talk to your doctor or pharmacist if you are unclear about how to take your bowel cleansing medication, prepare the solution, when to take it or any other questions you have.

Tips when taking bowel cleansing medicines

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 doctor or pharmacist 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 clear flavouring. 
  • 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 (e.g. 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: because bowel cleansing medicines cause multiple and sometimes urgent bowel motions, it is important to stay close to a toilet. You may pass your first bowel motion from 30 minutes to four hours after you first start taking the medicine. 
  • Sore bottoms: 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 flushable wet wipes (baby wipes) instead of toilet paper may also help.
  • Ask about your regular medicines: if you are taking regular medicines for other conditions, ask your doctor 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. 

Precautions before starting bowel cleansing medicine

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

If so, it’s important that you tell your doctor or pharmacist 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.

What are the side effects of bowel cleansing medicines?

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

Learn more

Examples of bowel preparation schedules

Each hospital will have its own bowel preparation schedule. Here are a few examples:


  1. Bowel cleansing preparations New Zealand Formulary

Additional resources for healthcare professionals

Glycoprep-C Medsafe, NZ
Moviprep Medsafe, NZ
Moviprep Orange Medsafe, NZ
Klean-prep Medsafe, NZ
Phospho-soda Medsafe, NZ
Picoprep Medsafe, NZ
Picosalax Medsafe, NZ
Prepkit-C Medsafe, NZ
Managing constipation in older people BPAC, NZ, 2019

Credits: Sandra Ponen, pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 05 Aug 2019