Getting Your Bowel Ready

For the endoscopist to get a clear view, your bowel needs to be completely empty beforehand. You'll be given a laxative preparation to take in the days before your appointment, along with instructions to follow a special, low-fibre diet and stick to liquids only for a period before the test — it's important to follow these instructions precisely, since incomplete bowel preparation can mean the test needs repeating.

If you take regular medication — particularly blood-thinning medicines such as warfarin or clopidogrel, or diabetes medication including insulin — you'll be given specific instructions about what to do beforehand, since some may need adjusting or pausing. Bring a list of your medicines, or the medicines themselves, to your appointment.

On the Day

You'll need to stop eating and drinking beforehand, as instructed in your appointment letter, and should bring any medicines you take with you. A nurse will talk you through what to expect and ask you to change into a hospital gown.

To help you feel more comfortable, you may be offered options such as sedation, pain relief, or a gas and air mixture — not every hospital offers all of these, so it's worth asking what's available. You'll be asked to sign a consent form confirming you understand the risks and agree to go ahead. If you have sedation, you won't be able to drive for 24 hours afterwards, so you'll need someone to collect you.

During the test, you may feel some discomfort or bloating from the gas used to help see the bowel clearly — you can ask for the procedure to pause at any point if needed.

How Safe Is It?

Colonoscopy is a very safe, routine procedure, and your doctor will always weigh up the benefits against any possible risks before recommending it. Mild bloating or cramping afterwards is common, caused by the gas used during the test, and usually settles within a few hours.

If a biopsy is taken or a polyp removed, some light bleeding from the bottom is fairly common afterwards and usually stops on its own within a day or two — contact the endoscopy unit if bleeding is heavy or continues. More serious complications, such as a tear in the bowel wall, are rare, but can occasionally need further treatment or surgery to repair.

Very occasionally, the procedure can't be completed on the day — for example if bowel preparation wasn't thorough enough, or the test proves too uncomfortable — in which case it may need to be repeated, or an alternative test suggested instead. As with any test, there's also a small chance an abnormality could be missed, though colonoscopy remains one of the most accurate ways of examining the bowel.