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Bowel Preparation before Surgery

This leaflet tells you how to prepare your bowel for your surgery using Klean-Prep. Your surgeon will have already discussed your planned surgery with you prior to your pre assessment appointment.

What is Klean-Prep?

Klean-Prep is a strong bowel cleansing agent which comes in sachets of white powder. To take it, the powder must be dissolved in water in a jug, when dissolved it becomes a clear colourless solution which is ready to drink.

Why do I need it?

Klean-Prep is given to ensure that your bowel is empty and clean before surgery. 

Before taking Klean-Prep

Please read the back of the Klean-Prep packet. If you answer yes to any of the following questions and they were not discussed at your pre assessment appointment please contact the colorectal nursing team on the telephone numbers provided at the end of this leaflet.

  • Are you allergic to any of the ingredients listed on the packet?
  • Are you taking warfarin or clopidogrel tablets?
  • Are you a diabetic on insulin or tablets?
  • Do you suffer from any kidney disease?
  • Do you suffer from phenylketonuria?

Pregnancy and breastfeeding

Klean-Prep should only be used during pregnancy or whilst breastfeeding if considered essential by your doctor.

Please advise your doctor if you suspect you are pregnant.

Driving and using machines

Klean-Prep should not affect your ability to drive or use machines.

When do I take Klean-Prep?

You will start your Klean-Prep the day before your hospital admission. If you work you will need to take the afternoon off work on this day. You should expect frequent bowel actions starting within one to two hours of starting your Klean-Prep. Some abdominal cramping is normal, stay within easy reach of the toilet.

  • You should have your last meal at 12 midday; you should not eat any more solid food until after your surgery.
  • You may drink black tea, black coffee and soft drinks throughout the day. You can add sugar if you like but no milk in any form, no alcohol.
  • If you take oral medication please make sure you take it at least one and a half hours to two hours before starting your Klean-Prep otherwise it may be flushed out of your system before it has had chance to work.
  • At 4pm start to take your Klean-Prep.
  1. Fill a jug with one litre of cold water (1 ¾ pints).
  2. Empty the contents of one sachet of Klean-Prep into the water.
  3. Stir until the solution is clear
  4. Drink one glass full ( ¼ litre or ½ pint) of Klean-Prep about every 15 minutes until you have drunk it all.
  5. It should take you one to one and a half hours to drink this.
  6. Once you have finished the Klean-Prep, make up and take the second sachet in the same way.

You should have taken both sachets by 7pm. You should be starting to have watery bowel motions so stay near a toilet.  

What can I expect?

Klean-Prep can begin to work within one to two hours of taking it. You will open your bowels frequently and eventually your motions should change from soft to loose and lastly to watery.

Stay close to a toilet all day as you will use it regularly.

You may experience some abdominal cramp, this is normal in some people.

The skin around your bottom can become red and sore due to frequent diarrhoea. A barrier cream such as Vaseline or nappy rash preparations can protect the skin. The soreness is temporary and will disappear in a few days.

Are there any side effects from Klean-Prep?

You may experience headaches, nausea, and sometimes vomiting. Abdominal bloating can occur and less frequently abdominal cramps. If you feel bloated or get stomach cramps try taking the Klean-Prep more slowly.

People are rarely allergic to Klean-Prep, however there have been some reports of itchy skin.

What do I do the morning of my hospital admission?

At your pre-assessment appointment you will have been given a time to stop drinking. You may drink clear fluids until then. You will need to stop drinking altogether at this time, this is part of the preparation required for your operation and anaesthetic.

Attend for your hospital admission at the time you have been told.

If you require any further advice or information regarding your bowel preparation you may contact;

The colorectal nursing team    (Monday to Friday 9am – 5pm)0191 445 3152
Out of hours contact numbers (Monday-Friday 5pm-9am)

(Saturday and Sunday)
Treatment centre level 2           
Ward 9                                      
0191 445 3005

0191 445 2009

The Patient Advice and Liaison Service (PALS) can provide help, advice and support to patients, relatives or carers who have any questions or concerns regarding their health care. PALS are unable to give medical advice. You can contact PALS on free phone 0800 953 0667 Monday-Friday, 9.00am-5.00pm. An answer phone is available outside of these hours and calls will be returned the next working day.

Acknowledgements, Mary Ritchie, Bowel Cancer Screening, Queen Elizabeth Hospital.

Data Protection

Any personal information is kept confidential.  There may be occasions where your information needs to be shared with other care professionals to ensure you receive the best care possible.

In order to assist us improve the services available your information may be used for clinical audit, research, teaching and anonymised for National NHS Reviews.  Further information is available in the leaflet Disclosure of Confidential Information IL137, via Gateshead Health NHS Foundation Trust website or the PALS Service.

This leaflet can be made available in other languages and formats upon request.