A colonoscopy is a medical procedure used to examine the inside lining of your large intestine (colon) using a long, flexible tube with a camera, called a colonoscope. It allows your doctor to check for conditions such as inflammation (colitis), Crohn’s disease, diverticulosis, polyps, or tumors.
Sometimes the procedure also includes a quick look at the very end of the small intestine (called the terminal ileum). During the exam, your doctor may take small tissue samples (biopsies) and remove any polyps if needed.
Polyps are small growths on the lining of the colon. While most are not cancerous, some can develop into colon cancer over time. That’s why, if it’s safe, your doctor will usually remove any polyps during the procedure. These are then sent to a lab for testing.
If a polyp is too large or difficult to remove safely during the colonoscopy, your doctor will discuss the next steps with you afterward.
For your doctor to get a clear view of your bowel, it needs to be empty. This is why you’ll need to follow a special bowel preparation process the day before the procedure. (You can find detailed instructions here.)
Key tips:
Stay well hydrated throughout the preparation.
Stop all fluids 4 hours before your scheduled admission.
Some medications may need to be stopped days before your colonoscopy. Please discuss this with your gastroenterologist ahead of time. Key points include:
Blood thinners (like aspirin, Clopidogrel, Warfarin, Xarelto, Pradaxa): These may need to be stopped up to a week prior.
Diabetic medications and insulin: Dosages might need to be adjusted the day before and morning of the procedure.
Iron supplements: Stop 7 days before.
Anti-inflammatory medicines: Stop 2 days before.
You can usually take your other regular medications as normal.
When you arrive at the hospital, the nursing team will welcome you and get you ready. You’ll meet with the anaesthetist, who will insert a small drip (IV) and give you a sedative to help you relax. The sedation used isn’t a full general anaesthetic, but it ensures you’re comfortable and likely won’t remember the procedure.
The colonoscopy typically takes about 30 minutes. Your doctor will gently introduce some gas to expand the bowel for better visibility—this might cause a bit of bloating or mild cramping afterwards, but it’s temporary.
Colonoscopy is generally very safe, but as with any procedure, there are small risks to be aware of:
Perforation (a tear in the bowel) is rare but serious and may require surgery.
Bleeding can occur, especially if polyps are removed or if you’ve been on blood thinners.
Reactions to sedation are uncommon but may include low blood pressure or allergic responses.
Dehydration from bowel prep is possible but can be avoided with good fluid intake.
It’s important to note that while colonoscopy is the most accurate test for detecting issues in the colon, no test is perfect. If the bowel isn’t well cleaned, it can be harder to detect problems.
Once the procedure is complete, you’ll be taken to recovery. Some mild bloating or cramping is normal and usually fades quickly.
Your gastroenterologist will speak with you before you leave, but you might not remember everything due to the sedation. You’ll receive a written summary of the findings, and a report will also be sent to your GP. If biopsies were taken or polyps removed, your doctor will follow up with you in the days after the procedure.
Important:
For the rest of the day:
Do not drive, work, drink alcohol, or sign important documents.
Arrange for an adult to take you home and stay with you until the next day.
Complications are uncommon, but if you experience severe pain, vomiting, or bleeding that night, contact your hospital or gastroenterologist right away. In an emergency, call 000.
For more detailed information, you can also visit the Gastroenterological Society of Australia website: www.gesa.org.au