What does a colonoscopy involve? A step-by-step guide
Specialist guide written and reviewed by Dr Goutham Sivasuthan — FRACS, GESA-accredited.
TL;DR. A colonoscopy is a 20–40 minute procedure under sedation that lets your specialist examine the entire large bowel using a thin flexible video camera. The procedure itself is painless and you won’t remember it. The most important — and slightly inconvenient — part is the bowel preparation the day before. Most patients are home within 2–3 hours of arriving at the day-surgery facility.
The week before
A few days before your colonoscopy, we’ll send you written instructions including a recipe for a low-residue diet for the last 1–2 days and a prescription for the bowel preparation drink.
You’ll also review your medications. Most can be continued. Blood thinners (warfarin, apixaban, clopidogrel) and some diabetes medications may need to be paused or adjusted — we’ll guide you specifically. Iron tablets should usually be stopped 5–7 days before.
The day before — the bowel prep
Bowel preparation is the part of the colonoscopy that patients find least pleasant. You drink a measured volume of a laxative solution over a few hours, which cleans out the bowel completely. A clean bowel is non-negotiable — the specialist literally cannot see the lining of the bowel if there is debris in the way, and incomplete prep means a higher chance of missing a polyp or being asked to repeat the procedure.
Modern prep regimens are much better tolerated than older ones — usually split-dose (half the night before, half the morning of), in palatable flavours. Stay close to a bathroom, drink plenty of clear fluids alongside the prep, and treat the day as a quiet one.
See our dedicated prep guide for a full walkthrough including timing, tips and what to expect.
Arriving at the day-surgery facility
On the day, you’ll arrive fasted (no food, clear fluids only, then nothing from 2 hours before). A nurse will check you in, confirm your consent and medications, and put a small cannula (drip) in your hand.
The specialist anaesthetist will see you to discuss the sedation and answer any questions. You’ll change into a gown and walk to the procedure room. The whole pre-procedure phase is usually 30–45 minutes.
The procedure itself
The anaesthetist gives the sedation through the cannula. Within a minute or two, you’ll be asleep. You won’t feel anything during the procedure and won’t remember it afterwards — this is deep conscious sedation, not a general anaesthetic, but the experience is similar.
The colonoscope — a thin, flexible tube with a high-definition camera at its tip — is gently passed through the anus and advanced around the curves of the colon. The specialist examines the lining carefully on the way in and again on the way out (most polyps are spotted on the way out).
If polyps are found, they are removed during the same procedure through the scope, painlessly. Biopsies of any concerning areas are taken in the same way. The procedure itself takes 20–40 minutes depending on what’s found and removed.
Waking up
You’ll wake up in recovery, drowsy and possibly a little bloated from air introduced during the procedure (this passes within an hour or two). The specialist will speak with you to explain what was seen and what (if anything) was removed.
Once you’re awake, tolerating fluids, and have walked safely, you’ll be discharged into the care of your support person. You cannot drive, work or sign legal documents for 24 hours.
The next few days
Most patients eat lightly the rest of the day and return to normal the next morning. A small amount of bloating, wind and possibly some streaks of blood (if a polyp was removed) is normal for the first 24 hours.
Biopsy results take 7–10 days. The specialist sends a written report to you and your GP, and arranges a follow-up if needed.
About your specialist — Dr Goutham Sivasuthan
Dr Goutham Sivasuthan is an Australian-trained Fellow of the Royal Australasian College of Surgeons (FRACS), with conjoint accreditation by the Gastroenterological Society of Australia (GESA) in both upper GI endoscopy and colonoscopy. He completed his medical degree at the University of Queensland and his advanced training across Brisbane’s tertiary hospitals.
Dr Goutham consults and operates exclusively at Brisbane-region day-surgery and hospital facilities, and is the only clinician you’ll meet through your care — from your first consultation, through your procedure, to your follow-up. He is committed to no-gap care for insured patients and transparent pricing for everyone else.
Frequently asked questions
Will I feel anything during the procedure?
No. You’ll be sedated and won’t feel the scope at any point. Most patients describe it as feeling fully asleep.
How long does the whole day take?
From arrival to discharge, plan on 2–3 hours total. The procedure itself is 20–40 minutes; the rest is admission, sedation and recovery.
What if I can’t tolerate the prep?
Tell us in advance — there are alternatives for patients who can’t tolerate large volumes of liquid. Don’t suffer through it in silence; an incomplete prep is much worse than a difficult one.
Can I have someone drive me home other than family?
Yes — a friend, neighbour, taxi or rideshare with someone accompanying you is fine. You just cannot be alone and you cannot drive yourself.
What if a polyp is found?
It is removed during the same procedure, painlessly, through the scope. You’ll be told straight away in recovery, and the tissue is sent for pathology to confirm what it was.
This article is part of our specialist series on bowel and gut health. For the full overview, see our main service page.
Have a question? Talk to a specialist.
Call us on 07 3733 1551 or request a booking online — most patients are seen within a couple of weeks.
