1 day before your colonoscopy

Colonoscopy diet advice and bowel preparation


Take your regular morning medicines, unless you have been instructed otherwise.

Try to take your usual morning medicines before 10am and your evening medicines after 9pm. Your body may not fully take in medicines between these times. This is because of the bowel preparation solution that you will have.

If you need any advice about when to take your medicines, please contact the pharmacy medicines helpline on 020 7188 8748 (open Monday to Friday, 9am to 5pm).

Stop taking any bulk-forming laxatives (which create a heavy, more liquid-like poo that is softer and easier to pass). These include:

  • isphaghula husk (such as Fybogel®)
  • methylcellulose (Celevac®)
  • bran
  • sterculia (Normacol®)

Food and drink

Have a light breakfast, such as boiled egg on toast (white bread), no later than 9am.

After breakfast, do not eat any solid food until after your test.

Drink clear fluids only today. They may include:

  • water
  • squash
  • fizzy drinks
  • clear strained soup
  • clear stock

Try to drink 2 litres (about 8 to 10 glasses) in total throughout the day (not including the bowel preparation solution).

You can drink tea or coffee with a small splash of milk. Do not drink alcohol.

Bowel preparation

You need to start taking bowel preparation solution the day before your colonoscopy.

Read more about what to expect from taking bowel preparation solution.

Please follow the instructions and timetable below for the solution that you are taking. Do not follow the instructions on the packet.

The solutions taste better if they are served chilled. You may want to mix the solutions in advance and keep them in the fridge. You need to use them within 24 hours of being prepared.

At 4pm

Take 4 senna tablets from the pack with a glass of water.

Read more information about taking senna tablets.

At 5pm

Mix 1 sachet of sodium picosulphate with 150ml of water. Do this in a large glass or jug, as the mixture may fizz over.

Stir the solution for 2 to 3 minutes. If the solution gets warm, allow it to cool before you drink it. You can add more water if you want to dilute the solution (make it weaker).

Please drink the preparation at once or, if you are drinking slowly, finish it within an hour.

At 2pm

Empty the contents of 1 sachet of Klean-Prep into 1 litre of water and stir until it is dissolved. Drink this over 1 hour to 1 hour 30 minutes.

At 4pm

Dissolve the second sachet of Klean-Prep and drink as above.

At 6pm

Dissolve the third sachet of Klean-Prep and drink as above.

At 4pm


  • 1 sachet A and
  • 1 sachet B

of Moviprep into 1 litre of water and stir until it is dissolved.

Drink this over 1 hour to 1 hour 30 minutes.

Ref number: 3993/VER2
Currently under review

A list of sources is available on request

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

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