It is essential that your bowel is empty for this investigation. In order for your bowel to be empty please follow the instructions below.

7 days before your appointment

If you have diabetes or are taking any medication that thins your blood, other than aspirin (which you can remain on) please contact the relevant Endoscopy Unit on the Medication Advice Line (answer phone). The telephone number is at the end of this page.

Stop taking any of the following medication:

  • Imodium® (loperamide)
  • Codeine phosphate
  • Lomotil® (co-phenotrope)
  • Iron tablets
  • Fybogel® (ispaghula husk)

Please note all other medications such as heart tablets and blood pressure tablets should be continued as normal, including on the day of your test.

2 days before your appointment

Start on a low fibre diet. Eat foods only from the following list:

  • Eggs – boiled or poached
  • White fish
  • Chicken
  • Lean meat for example beef, lamb, veal or ham
  • Gravy using stock cubes (white flour or corn flour to thicken)
  • White bread or rolls (no seedy bread)
  • Potatoes – boiled or mashed (no skins)
  • Pasta/noodles
  • White rice
  • Butter/margarine – use sparingly
  • Clear jelly (not red) without fruit pieces
  • Sugar/honey/syrup/treacle/jelly(e.g. bramble jelly)/jams/marmalade (without peel)
  • Boiled sweets or clear mints
  • Tea/coffee
  • Herbal tea - clear (avoid red colours)
  • Lucozade®, water, soda water
  • Fizzy drinks, squashes, clear fruit juice (no bits)
  • Quorn, tofu, textured vegetable protein
Information:

Do not fry food

Avoid seeds and sweetcorn especially

Drink plenty of fluids

1 day before your appointment

At 8:00am have a good breakfast of food taken from the low fibre list. After this do not eat any solid food.

Drink plenty of clear fluid such as tea/clear herbal tea/coffee/fruit squash/carbonated water drinks or plain water). You may have small amounts of milk in tea or coffee. Clear jelly (not red) is allowed.

At 2.00pm dissolve 1 large sachet and 1 small sachet of Klean Prep in 2 pints (1 litre) of water and drink it over 1 hour.

At 4:00pm dissolve 1 large sachet and 1 small sachet of Klean Prep in 2 pints (1 litre) of water and drink it over 1 hour.

At 6:00pm dissolve 1 large sachet and 1 small sachet of Klean Prep in 2 pints (1 litre) of water and drink it over 1 hour.

Drink a further 2 pints (1 litre) of water before going to bed.

Morning of your appointment

At 6.00am dissolve 1 large sachet and 1 small sachet of Klean Prep in 2 pints (1 litre) of water and drink it over 1 hour.

Drink a further 2 pints (1 litre) of clear fluid during the morning.

Clear fluids only should be taken this morning – no solid food.

It is important that you do not become dehydrated.

Clear fluids can be drunk right up to the time of your appointment.

You may bring a bottle of water with you to your appointment.

Please note: Klean Prep may be flavoured with clear fruit juices (such as apple) or clear squash (such as lemon). This can be made up in advance and chilled in the fridge.

You should expect frequent bowel actions and eventually diarrhoea. Some cramping in your stomach is normal. Your bottom may become quite sore. Please use a barrier cream to stop any irritation. There are many products available from your local pharmacy.

If you have any difficulties

Sometimes, the bowel preparation may cause side effects such as nausea, vomiting, abdominal fullness and bloating, abdominal cramps, fatigue, sleep disturbances, anal irritation, urticaria and allergic reaction. If you have any allergies, please check the preparation ingredients before taking.

Do not take if you suffer with the following:

  • Hypersensitivity (allergic reactions/sensitivities)
  • Congestive cardiac failure
  • Gastrointestinal obstruction or perforation

If you feel that you will be unable to complete the bowel preparation successfully, please contact the relevant Endoscopy Unit for advice.

Contact information

Medication Advice Line (answer machine)

If you have any questions relating to your medication, please leave a message and a member of staff will return your call:

Cheltenham General Hospital

Tel: 0300 422 3370

Gloucestershire Royal Hospital

Tel: 0300 422 8232

Other Endoscopy Units

Cirencester Hospital

Tel: 0300 421 6294

Monday to Friday, 8:00am to 6:00pm

Stroud General Hospital

Tel: 0300 421 8073

Monday to Friday, 8:00am to 6:00pm

Reference number GHPI1138_04_23
Department Endoscopy
Review due April 2026