A colonoscopy is a day procedure in which a thin, flexible camera is used to examine the full length of your colon (large bowel). It allows problems to be seen directly and treated on the spot — most importantly, polyps can be removed before they ever become bowel cancer.
What is a colonoscopy?
A colonoscopy uses a colonoscope — a long, thin, flexible instrument with a camera at its tip — to examine the lining of your entire colon and rectum. The procedure is performed under sedation, so you are drowsy and comfortable and remember very little afterwards.
If anything unusual is seen, such as a polyp or an area of inflammation, it can usually be examined or removed during the same procedure. Tissue samples (biopsies) can also be taken and sent to a laboratory for analysis.
Why you might need one
Prof. Mittal may recommend a colonoscopy if you have:
- A positive FOBT or iFOBT (faecal occult blood test) from the National Bowel Cancer Screening Program — a positive test should always be followed up with colonoscopy
- Symptoms such as blood in your bowel motions, a change in bowel habit, unexplained weight loss, ongoing diarrhoea or abdominal pain, or unexplained iron deficiency anaemia
- A family history of bowel cancer or polyps, particularly in a parent, sibling or child diagnosed at a young age
- A personal history of polyps or bowel cancer, where regular surveillance colonoscopy is recommended
- Abnormal findings on other imaging or blood tests that need direct examination
What happens on the day
Colonoscopy is performed as a day procedure at the hospital or endoscopy centre. You arrive fasting, having completed your bowel preparation. After checking in:
- You change into a gown and meet the nursing and anaesthetic team
- Sedation is given through a drip in your arm — most people drift off and remember little
- The colonoscope is gently passed around the colon while the bowel lining is examined — this usually takes 30–60 minutes
- Any polyps found are usually removed, and biopsies taken if needed
- You wake up in recovery, rest for a while, and Prof. Mittal discusses the initial findings with you before you go home
Bowel preparation
A clean bowel is essential for a safe and complete examination. Prof. Mittal’s standard preparation is MOVIPREP, and the plan below is the same one you will receive with your booking:
Three days before
- Avoid seeds and grains — multigrain and wholegrain breads, high-fibre cereals, brown rice, tomatoes, kiwi fruit, passionfruit, lentils, berries, sesame seeds and corn
- Take one sachet of Movicol each day (if you are usually constipated, continue your usual laxatives and extra Movicol)
- Stop iron tablets, semaglutide (Ozempic) and fish oil
- If you take blood thinners (clopidogrel, warfarin, rivaroxaban, dabigatran, apixaban), contact the rooms — most need to be stopped 5 days before. You may continue aspirin unless advised otherwise
- If you are diabetic, contact the rooms about your medications — SGLT2 inhibitors (Forxiga, Jardiance, Xigduo and similar) must be stopped 3 days before, and insulin doses usually need reducing
The day before
- Until 12 noon, eat only white foods: white bread, rice or pasta, Rice Bubbles, eggs, cheese, milk, plain yoghurt, skinless chicken breast, white fish, peeled potatoes, plain rice crackers or noodles, vanilla ice cream, custard, white chocolate
- After 12 noon, clear fluids only — no further solid food. Water, lemonade, sports drinks, clear cordial, pulp-free fruit juice, black tea and coffee, strained clear soups and broths, clear ice blocks and plain jelly. Avoid strongly coloured liquids, milk and cloudy juices
- At 5–6pm, drink the first dose of MOVIPREP (Sachet A + Sachet B dissolved in 1 litre of water, cooled in the fridge; a straw can help with the taste). Expect loose bowel movements within 1–3 hours — stay near a toilet
- Keep drinking clear fluids (at least 3–4 glasses) through the evening. A headache usually means dehydration — drink more; paracetamol is fine
On the day
- 4 hours before you are due at hospital, drink the second dose of MOVIPREP with more clear fluids
- Nothing to eat or drink from 3 hours before arrival — including chewing gum and sips of water. Your stomach must be empty for sedation (important morning medications may be taken with a sip of water before this time)
MOVIPREP is available from your pharmacy without prescription (plain, orange or blackcurrant flavour). Follow the instructions closely — if the bowel is not well cleared, polyps can be missed and the procedure may need repeating. If the laxatives do not seem to be working, take an additional dose of MOVIPREP or similar.
Recovery
Almost everyone goes home the same day. You may feel bloated or pass wind for a few hours — this is normal and settles as air from the procedure disperses. Because of the sedation:
- You must arrange for a responsible adult to drive you home and stay with you overnight
- You cannot drive, sign legal documents, drink alcohol or operate machinery for 24 hours
- Most people return to normal activities the next day, including work
Risks
Colonoscopy is a very safe procedure, and the risks are rare. It is worth knowing them honestly:
- Bleeding — can occur at the site of a polyp removal or biopsy. It is usually minor and settles on its own; occasionally it requires further treatment or a repeat procedure
- Perforation (a small tear in the bowel wall) — rare, affecting roughly 1 in 1,000 patients, and even less commonly when no polyp is removed. If it occurs, it may require antibiotics, admission to hospital, or rarely surgery to repair
- Reactions to sedation — usually minor, such as a tender vein or temporary light-headedness
- Very rarely, a procedure cannot be completed — for example if the bowel is not fully cleared — and needs repeating
Prof. Mittal will discuss your individual risks with you and answer any questions before you consent to the procedure.
How it works
- 1. Get in touch — book online or message the rooms with your referral and any test results, including your bowel screening test result
- 2. Scheduling & preparation — the team books your procedure at a convenient hospital and gives you your bowel preparation instructions and medication plan
- 3. Procedure day — you arrive fasting, have your colonoscopy under sedation, and go home the same day with your adult escort