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 (avoid 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

Do not fry food

Avoid seeds and sweetcorn especially

Drink plenty of fluids

1 day before your appointment

Have a light breakfast no later than 9:00 am; food must be taken from the low fibre list. After this do not eat any solid food.

Drink plenty of clear fluid (tea/clear herbal tea/coffee/fruit squash/ carbonated water drinks or plain water).

At 6:00 pm open the carton and remove the Dose 1 sachet. Pour the contents of the Dose 1 sachet into a measuring container that can hold 500ml of fluid. Add water to make up to the 500ml and stir until all of the powder has dissolved. Drink this over 1 hour.

Drink a further 500ml of water afterwards.

If you are thirsty drink plenty of clear fluids.

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 if you think it is necessary. A barrier cream is a topical treatment used to place a physical barrier between the skin and contaminants which may irritate. There are many products available from your local pharmacy.

Morning of your appointment

At 6:00 am open the carton and remove the Dose 2 sachets

A and B.

Pour the contents of the Dose 2 sachets A and B into a measuring container that can hold 500ml of fluid.

Add water to make up to 500ml and stir until all of the powder had dissolved. Drink this over 1 hour with a further 500ml of water.

It is important that you do not become dehydrated. Clear fluids can be drunk up to 2 hours before the time of your appointment.


Do not drink in the 2 hours before your appointment.

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
  • Toxic megacolon or ileus
  • G6PD deficiency
  • Phenylketonuria
  • Hypermagnesemia
  • Renal impairment (kidney problems)
  • Rhabdomyolysis

If you are pregnant, please discuss with a doctor before taking the bowel preparation.

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

Printable version of this page

How to take your bowel preparation for a gastroscopy and colonoscopy am Plenvu GHPI1494_05_23 Department: Endoscopy Review due: May 2026 PDF, 216.1 KB, 4 pages
Reference number GHPI1494_05_23
Department Endoscopy
Review due May 2026