Getting your bowel ready for a colonoscopy is an important part of the process. A clean bowel helps your doctor see the lining of your colon clearly, making it easier to spot any problems like inflammation, polyps, or other abnormalities. It also ensures that any polyps found can be removed safely during the procedure.
There are three main steps to getting your bowel ready:
Start a Low-Residue Diet
About two days before your procedure, you’ll begin eating a low-fibre (low-residue) diet. This helps reduce the amount of waste in your bowel.
Switch to Clear Fluids
The day before your colonoscopy, you’ll move to a clear-liquid-only diet. This includes water, clear broth, apple juice, and jelly (avoid red or purple colors).
Take the Bowel Prep Medication
You’ll be given a special medication (usually in two or three doses) that helps empty your bowel. This often causes watery diarrhoea soon after taking the first dose—this is expected and means it’s working.
Bowel prep can cause dehydration and affect your body’s salt (electrolyte) levels. To stay safe and feel your best:
Follow the instructions exactly as prescribed
Drink plenty of clear fluids throughout the process to stay hydrated
The information here is a general guide. Your gastroenterologist will create a custom bowel prep plan based on:
The time of your procedure
Your overall health
Any medical conditions you may have (such as diabetes or kidney disease)
This personalised plan will explain:
What type of bowel preparation to use
When to take each dose
What foods and drinks to avoid
Whether any changes are needed to your usual medications
If you have diabetes or kidney disease, it's especially important to discuss this with your doctor during your consultation, as your prep may need to be adjusted for safety.
If you're unsure about anything related to your bowel prep, don’t hesitate to contact your gastroenterologist. You can also find additional resources on the Gastroenterological Society of Australia website: www.gesa.org.au