Gastrografin Preparation Sheet for CT Colonography (Morning Appointments)

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Morning Appointments Information

Important: If you no longer require this test or have recently had your bowel investigated, please let us know as soon as possible on 07826 513567

Your appointment date and time are shown on your appointment letter, sent separately. Please report to the CT reception in the X-ray department at the hospital where you are appointed, bringing this document with you.

You will need to stay close to a toilet on the day before the examination as the Gastrografin may have a laxative effect which can be extremely effective. 

If you are taking iron tablets please stop taking them 3 days before your scan. 

Please continue taking all other prescribed medications. If you have diabetes, please read the additional information provided.

You should have received a bottle of Gastrografin to drink as described below.

DO NOT drink the Gastrografin:

  • If you have previously had an allergic reaction to intravenous iodine-based contrast medium (X-ray dye injection). 
  • If you have difficulty in swallowing.

If so, please contact us on 07770 784911 Monday to Friday 9.00 a.m. to 4.00 p.m.

You will be asked to change into a hospital gown for the test, so you may wish to bring a dressing gown or coat with you to wear over the gown. 

If there is any chance of being pregnant, please notify the department. If you take oral contraceptives, the diarrhoea may reduce their effectiveness. Continue taking oral contraceptives but use other precautions for the remainder of that cycle.

The DAY BEFORE your scan

DO NOT eat any solid food. 

Please follow a LIQUID ONLY DIET. You can have clear soups (for example strained chicken noodle soup – not blended soups), vegetable Bouillon, jelly, custard, ice cream and yogurt (with no lumps), Complan drinks, Bovril and Oxo drinks, water, clear juices, fizzy drinks, coffee and tea (with milk if preferred).

Drink as much tea or water as you like but take at least a quarter pint (150 ml) of fluid every hour on the hour during the daytime.

At 10.00 a.m. drink half the bottle of Gastrografin (50 ml), mix with an equal amount of water. It may also be flavoured with fruit juice or cordial.

At 6.00 p.m. drink the second half of the bottle of Gastrografin (50 ml), as above.

ON THE MORNING of your scan

DO NOT eat any solid food, you may drink water or clear sugary drinks until your scan is completed.

You may be in the X-ray department for up to one hour.

After the examination, you can eat and drink normally.

Appointments will only be changed in cases of emergency.

If you are unable to attend please let us know as soon as possible as we may be able to offer this appointment to another patient. Please call 07826 513567 to change or cancel your appointment.

Summary of your bowel preparation plan for CT Colonography

3 DAYS BEFORE your scan

Stop any iron tablets you may be taking. 

Continue all other medication and any laxatives you normally take, until you come for your scan.

THE DAY BEFORE your scan

Do not eat any solid food, but clear soups etc. are allowed. Remember to drink plenty of fluids.

10.00 a.m. take the first dose (50 ml) of Gastrografin as described.

6.00 p.m. take the second dose (50 ml) of Gastrografin as described.

ON THE DAY of your scan

Please do not have anything to eat. You can continue to drink water or sugary drinks.

Please follow these instructions closely to make sure that your bowel is as empty as possible before the scan. Keeping to this diet will improve the accuracy of your scan.

General Trust Information

Patient Advice and Liaison Service (PALS)

PALS is a confidential service for people who would like information, help or advice about the services provided by any of our hospitals. Please call 0800 783 4372 between 9.30 a.m. and 4.30 p.m. or e-mail Please note that this service does not provide clinical advice so please contact the relevant department directly to discuss any concerns or queries about your upcoming test.

CTC GG bowel preparation MORNING appointment CMH/NPH V2.1. Created by JAM/KAS 2020. Version 2.1. Reviewed by VM October 2023. Next Review Oct 2026

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