A colonoscopy is a relatively painless procedure which allows a colorectal surgeon to do a thorough inspection of the bowel.

If you’ve been advised you might need a colonoscopy, you’ll undoubtedly have lots of questions. We’ve answered some of the most common questions about colonoscopies the Brisbane Colorectal team receive.

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On this page, we’ll answer the following questions:


What is a colonoscopy?

A colonoscopy is a relatively painless procedure which enables your bowel to have a detailed inspection.

During the procedure, your surgeon will use a colonoscope, which is a long, thin, flexible tube with a small video camera at the top. It’s also referred to as a scope. The colonoscope is passed through the rectum into the colon. This means the lining of the large intestine can be properly inspected, and it also allows for procedures such as biopsies and the removal of polyps.


Before the procedure, you’ll be given a light anaesthetic. In rare cases, patients are slightly aware of what is happening in the room, but it’s more likely you won’t remember the procedure at all.

Your safety is always our highest priority. The anaesthetic will be administered by an anaesthetist, who will also monitor your vital signs during the procedure and ensure you are as comfortable as possible.

Bowel inspection

Once you’re sedated and lying in a comfortable positive on your left side, the doctor will insert the flexible colonoscope through the anus and slowly guide it into the colon.

The small camera in the end of the colonoscope transmits images to the monitor, so the doctor can carefully examine the intestinal lining. Once the scope has reached the opening to the small intestine, it is slowly withdrawn, and the lining of the large intestine is carefully examined again.

Removal of polyps and biopsies

A polyp is a small tissue growth attached to the bowel wall. They are usually harmless, and common in adults.

However, most colorectal cancers begin as a polyp. Removing them early is an effective way of preventing cancer.

If polyps are found during the procedure, they will usually be removed using small tools called snares which are passed through a channel in the scope. Small tissue samples or biopsies of the bowel may also be taken and sent for assessment under a microscope.

Why do I need a colonoscopy?

A colonoscopy can detect inflamed tissue, ulcers and abnormal growth including polyps.

It can help doctors diagnose unexplained changes in bowel habits, abdominal pain, weight loss and bleeding from the bowel, as well as help detect early colorectal cancer. It also helps determine treatment of certain conditions such as bleeding haemorrhoids.

What happens after a colonoscopy?

After your colonoscopy, you will remain in the recovery area for an hour or two – until your sedation wears off. Once awake, you’ll be given something light to eat and drink.

You might feel a little bloated for an hour or so. In rare cases, patients might pass a small amount of blood. This will likely be due to the irritation of the anal canal, and is nothing to be concerned about.

Because of the sedation, it is very important you do not drive, travel on public transport alone, operate machinery or sign legal documents on the same day after your procedure. We strongly advise that an adult family member, relative or friend take you home and stay with you for the night. The next day, you can expect to be fully recovered and return to normal activity.

Are there any risks or side effects of a colonoscopy?

Complications can occur with any medical procedure, although complications from colonoscopies are rare.

In Australia, very few people experience serious side effects from colonoscopy and polyp removal – less than one in 1,000. The chance of complications depends on the exact type of procedure being performed and other factors, including your overall health.

Major bleeding after colonoscopy is rarely seen. If it does occur, it may require readmission to hospital, often a blood transfusion, and occasionally, another colonoscopy.

Colonoscopies very rarely cause injuries to the bowel lining, in fact it’s a less than one in 2000-3000 chance of it happening to you. If this does happen you will be readmitted to hospital for antibiotics, and possibly surgery.

It is possible to react to the anaesthetic, although this is also rare.

In a few cases, the colonoscopy is not successfully completed and might need repeating. This is typically due to poor preparation or technical difficulty.

If you have any of these symptoms in the hours or days after your colonoscopy, please contact your doctor’s rooms immediately or go straight to the nearest emergency department:


  • Severe abdominal pain
  • Black, tarry motions
  • Persistent bleeding from the anus
  • Fever
  • Other symptoms that cause you concern

Are colonoscopies accurate?

A colonoscopy provides the most accurate assessment of the lining of the colon. However, no test is 100% accurate and there is a risk an abnormality may not be detected.

in 2-8% of cases, a colonoscopy can miss serious lesions in the bowel. For serious lesions such as cancer, the chance is extremely low, but still present. If you have any recurrent or persistent symptoms after your procedure, please contact your doctor.

Can’t find what you’re looking for?

If you’ve been advised or suspect that you have a condition and it’s not listed here, please, call us on 07 3010 3360 and speak to our friendly team to see how we can help.