A colonoscopy is done to have a look inside the bowel. For this, the bowel must be completely empty.

You must prepare properly

4 days before.png

4 days before

  • Low-fibre food only
  • Drink one large cup of fluids every hour during the day
1 day before.png

1 day before

  • Stop solid food
  • Continue drinking plenty, but only clear fluids
  • Begin bowel prep
Morning appointment.png

Day of morning appointment

  • Stop fluids
Afternoon appointment.png

Day of afternoon appointment

  • Finish bowel prep
  • Then stop fluids

About bowel preparation

Watning circle saying No bowel prep, no procedureA few days before the procedure, you will need to start ‘bowel preparation’ to empty the bowel. This involves: 

  • taking medicines (called laxatives) to make you poo 
  • cutting down on how much fibre you eat  
  • stopping all food in the last few hours beforehand. 

Important instructions

The instructions given below are very important. If you do not stick to them, we will probably have to cancel the procedure because we will not be able to see inside your bowel clearly.
 
Black arrow icon.pngContact the endoscopy nurse helpline if you have any questions.

Effect of bowel preparation

The laxatives will cause repeated bowel movements and eventually diarrhoea.

These effects can start at any time after taking the laxatives. The urge to open your bowels can be sudden, giving you little time to reach a toilet. So, it is a good idea to stay within easy reach of a toilet.

The laxatives may also cause nausea, stomach cramps and bloating.

Very rarely, patient have a severe reaction to the laxatives.

Black arrow icon.pngContact your GP or go your nearest emergency department (A&E) if you feel significantly unwell, collapse or faint. Take this information sheet with you.

It is sensible to have a supply of the drinks you will need before starting your laxatives. See box A, below.

4 days before the endoscopy

4 days before.pngBegin preparation for your endoscopy four days before your appointment, when you wake up that morning.

Increase how much fluids you drink to 200 mls (one large cup) every hour. This is to make the laxatives work better.

Start eating only low-fibre food (see box B).

Cut down alcohol to no more than one small glass of wine or one small bottle of beer per day.

1 day before the endoscopy

1 day before.pngThe day before your appointment you must begin taking the laxatives, stop solid foods and drink plenty of clear fluids (see box A).

When you start this depends on what time your endoscopy is booked for. The tables, below, set out the details.

Morning endoscopy
(8am to 12.45 appointments)

Day before

  
3pm Stop all solid food until after endoscopy.
For the rest of the day, do not drink just water. Drink at least one additional litre of clear fluids (see box A). It is important you drink sugary drinks for the energy and savoury drinks for the salt. Otherwise, you may feel weak or dizzy and you may even faint.
5pm to 5.30pm  Take the first dose of Plenvu, labelled ‘Dose 1’. See box C.
5.30pm to 6pm Drink a further 500ml of clear fluid over 30 minutes. There is no need to rush.
8pm  Take the second dose of Plenvu, labelled ‘Dose 2 Sachet A’ and ‘Dose 2 Sachet B’. See box C.
8.30pm to 9pm Drink a further 500ml of clear fluid over 30 minutes. There is no need to rush.

Day of appointment

  
4 hours before Stop all fluids apart from sips of water.
2 hours before  Stop drinking water until after endoscopy.

Afternoon endoscopy
(1pm to 5.30pm appointments)

Day before

  
4pm Stop all solid food until after endoscopy.
For the rest of the day, do not drink just water. Drink at least one additional litre of clear fluids (see box A). It is important you drink sugary drinks for the energy and savoury drinks for the salt. Otherwise, you may feel weak or dizzy and you may even faint.
6pm to 6.30pm  Take the first dose of Plenvu, labelled ‘Dose 1’. See box C.
6.30pm to 7pm Drink a further 500ml of clear fluid over 30 minutes. There is no need to rush.

Day of appointment

  
7am      Take the second dose of Plenvu, labelled ‘Dose 2 Sachet A’ and ‘Dose 2 Sachet B’. See box C.
7.30am to 8am Drink a further 500ml of clear fluid over 30 minutes. There is no need to rush.
4 hours before Stop all fluids apart from sips of water.
2 hours before  Stop drinking water until after endoscopy.

Box A

Clear fluids Avoid

green tick

 

  • water
  • squash
  • fizzy drinks
  • apple juice, orange juice
  • black tea or coffee (sugar is allowed)
  • Oxo/Bovril/Marmite
  • Horlicks (made with water)
  • Ovaltine (made with water)
  • hot chocolate (made with water)
  • consommé
  • lemon or lime jelly
  • sorbet (no fruit bits)

red cross

 

  • milk, milkshakes
  • smoothies
  • red-coloured drinks
  • fruit juice with ‘bits’
  • alcohol
  • soup
  • ice cream

Box B

Low-fibre food you can eat

Foods to avoid  
Cereals  
green tickRice Krispies red crossAll breakfast cereals except Rice Krispies
Dairy  

milk, creamgreen tick

green tickbutter or spread

green tickcheese

green ticksmooth yogurts (no bits)

  
Soup  
green tickclear soups  
Protein  

green ticktender meat

green tickwhite fish

green tickeggs

green ticktofu, Quorn

red crossnuts, including coconut

red crossseeds

red crossnut roast
Fruit and vegetables  

green tickboiled or mashed potatoes (peeled)

green tickcourgettes (peeled), marrow flesh

green tickcucumber (peeled), cauliflower florets, parsnips (peeled), radish

green tickapples, bananas, pears, lychees (all fruit must be peeled)

green tickgrapefruit (avoid pith)

red crossjacket potatoes

red crossAll fruit and vegetables not mentioned on the ‘food you can eat’ list

red crossjuice with ‘bits’

red crossbeans and pulses
Bread and starchy food  

green tickwhite bread

green tickcream crackers

green tickwhite rice

green tickwhite pasta

green tickYorkshire puddings

red crossAvoid all bread except for white bread

red crossoatmeal, oat bran and oat germ

red crossrye flour

red crossbran
Preserves  
green tickmarmalade (no shred), honey, marmite red crossjams, pickles, chutney
Snacks and puddings  

green tickcrisps

green tickplain biscuits, such as Rich Tea, shortbread, malted milk or Nice biscuits

green tickplain madeira cake

green tickice lollies, ice cream

green tickplain or milk chocolate (no nuts/fruits)

 red crossdigestive biscuits
biscuits containing bran

Box C

How to take laxatives
  • The first dose of Plenvu needs a single sachet (labelled ‘Dose 1’). Empty the sachet into a jug. Add water to make up to 500ml. Stir until the powder has dissolved. This may take up to eight minutes so it is a good idea to prepare it in advance.

    Drink one glass every 10 minutes until the jug is empty. You can take it in slow sips, there is no need to rush. You may add ice if you wish.
     
  • The second dose of Plenvu needs two sachets (labelled ‘Dose 2 Sachet A’ and ‘Dose 2 Sachet B). Empty both sachets into a jug together. Add water to make up to 500ml. Stir until the powder has dissolved. This may take up to eight minutes so it is a good idea to prepare it in advance.

    Drink one glass every 10 minutes until the jug is empty. You can take it in slow sips, there is no need to rush. You may add ice if you wish.

Contact information

Endoscopy nurses helpline

Telephone:

020 8934 6614 (2pm to 4pm only)