Diet guide for colonoscopy prep
Easy-to-read guides for each phase of your preparation diet. Choose the section that matches where you are in your prep.
The morning of your procedure
Arrive prepared, on time, and with a support person
The day of your colonoscopy is about finishing any final prep steps, managing medications, and arriving safely. Most of the hard work is already done.
Gluten challenge for Coeliac testing
Your doctor is taking biopsies to check for Coeliac disease. For the test to be accurate, you need to keep eating gluten before the procedure.
- Continue eating normal amounts of wheat, barley, rye, and oats (if you usually eat them).
- If you are already on a gluten-free diet, speak with your doctor about a formal gluten challenge before the test. A common challenge is the equivalent of 2 slices of wheat bread daily for about 6 weeks.
- Do not start a gluten-free diet until after your procedure and your doctor has discussed the results with you.
- The low-fibre and clear-liquid diet instructions still apply, but choose gluten-containing refined options where possible (e.g., white bread, plain wheat biscuits, white pasta) until your prep phase begins.
If you have already cut out gluten, let the clinic know before your appointment. Your doctor may need to reschedule the biopsies or adjust the advice.
What to do
Complete these steps unless your doctor gave you different instructions.
Stop clear liquids 2 hours before arrival
This helps reduce the risk of aspiration during sedation. Small sips of water with approved medications are usually allowed up to 2 hours beforehand.
Take only approved medications
Take blood pressure, heart, or other medications your doctor told you to continue. Avoid blood thinners, diabetes medications, or supplements unless specifically instructed.
Arrange a ride home
You will receive sedation and cannot drive yourself. Arrange for a responsible adult to take you home. Public transportation or rideshare alone is not recommended.
Confirm your appointment time
Double-check arrival time and location. Arrive on time with your Medicare Card, Health Insurance Details, a current medication list, and a ride home.
What to avoid
Avoid these common mistakes on the day of your procedure.
No solid food
Continue fasting from the clear-liquid phase.
No gum or mints
These can stimulate saliva and digestive juices.
No smoking or vaping
Avoid these on the morning of the procedure.
No alcohol
Avoid alcohol the night before and the day of.
No jewelry or valuables
Leave them at home for safety and comfort.
No driving after sedation
Plan transportation in advance.
What to bring
Identification
Photo ID and insurance card
Medication list
A current list with dosages
Comfort items
Loose clothing and a light jacket
Support person
Someone to drive you home
Questions
A written list for your doctor
Payment
Copay or payment method if required
When to call your doctor
Contact your care team if you are vomiting and cannot keep fluids down, have severe abdominal pain, notice heavy rectal bleeding, develop a fever, or feel severely weak or dizzy. These symptoms are uncommon, but it's important to get guidance.