What happens during a colonoscopy?

This is one question that I often get asked, that may seem like an odd thing to ask someone but as I am sometimes seen as the voice of poo I get a LOT of poo based questions!!

So you have been told you need to have a camera up your bum and it is TERRIFYING! The reason you are having the test is diagnostic, so doctors can take a look inside your colon.  The actual reason can be so varied but usually because there has been unusual activity, diarrhoea, bleeding, mucus, incontinence etc.

Not only are you dealing with the worry of what they will find (and I know we all assume cancer, and though that can be the case, there are SO many other reasons you are having problems, so don’t scare yourself into hysterics before you get any results!). But many people feel embarrassed to discuss with others and the thought of someone looking up your bum is just mortifying.  This happens with ‘poo diseases’, if you were suspected to have diabetes and were going for blood tests, you shouldn’t feel any shame but because it is from the bottom, it can feel ridiculously embarrassing.

Just remember that these medical professionals do this every day.  They will not be embarrassed, they won’t be giggling or thinking what an odd shaped bottom you have! They see thousands of bums a year and I promise you, they are not judging you!

So what happens? Firstly let me say, I am not medically trained and this is my experience of having many colonoscopies over the past 11 years.  It is really important that if you have any specific medical questions that you speak to your doctor.

Which type?

Well there are a few different ‘up the bum’ cameras.

Flexible Sigmoidoscopy

This is used to look at the inside of the large intestine from the rectum through to the sigmoid but not sufficient  in the ascending or transverse colon (two-thirds of the colon).

Rigid Sigmoidoscopy

This is a procedure done to look at the rectum and lower colon.


This is an examination of the large bowel and the end part of the small bowel with a camera on a flexible tube passed through the anus.

Colonoscopy is similar to sigmoidoscopy—the difference being related to which parts of the colon each can examine. A colonoscopy allows an examination of the entire colon. A sigmoidoscopy allows an examination of the distal portion (about 600 mm) of the colon.

sigmoidoscopy colonoscopy colon


A Pouchoscopy is a procedure to examine the lining of your ileo-anal pouch for any inflammation, abnormal growths or tissue.  This is for people who have had their bowels removed and a ‘jpouch’ or ileoanal anastomosis formed.

j pouch pouchoscopy


The colon must be completely clear of poo for the test to be performed properly. For a few days, you may be  required to follow a low fiber diet and on the day before the scope, you will be given a laxative preparation.

There are different types of bowel prep but all of them have the intention of clearing EVERYTHING out.  Most require you to drink the medication mixed with a lot of water.  It can be really difficult to stomach this but it is vital you complete all the medication given to you.  It will be explained to you how to take your type of medication but if you have any questions, then do speak to your doctor.

You will want to stay at home and close to the toilet once you start your bowel prep.  Trust me on this one, STAY CLOSE to the loo!

colonoscopy prep lol


What next?

Once you get to the hospital, it is necessary to remove your clothes and change into a gown before the procedure.  You will be taken through to the room where there may be a few medical folk in the room.  You will be asked to get on the examination table and lay on your side with your knees up towards your chest, the back of your gown is open to the doctor.

Some people choose to have sedation to help them through the procedure.  In my own experience I could handle the pouchoscopy and sigmoidoscopies without sedation, there was very minimal discomfort.  But for the colonoscopy, I have the sedation as the camera is going further into the colon and I personally struggled without.  You could also be offered gas and air. Speak to your doctor beforehand to decide what (if any) pain relief is needed.

If you have the sedation, you will generally have a canula inserted into a vein for the sedative to be pushed through into your blood stream, once it goes in, it acts very quickly and you may feel light headed and like you are a bit drunk!  You should feel relaxed and perhaps sleepy and in a  dreamlike state.

You may also have a clip on your finger to keep check on your pulse and perhaps a blood pressure cuff.  Staff are with you all the way through, at every scope I have had, there has been a nurse to sit by me and speak to me throughout the procedure.

The first step is usually a digital rectal examination, where the doctor inserts a finger into your anus. The endoscope is then passed through the anus, up the rectum into the colon.The endoscopes have multiple channels for instrumentation, air, suction and light etc.

Colonoscopy position



The bowel is expanded with air to maximise visibility, this can feel uncomfortable and make you have the sensation that you need to poo.  As you lay on your side, you may be able to see the screen the the doctor watches so they can see in real time the inside of your colon, some people may not want to watch the screen but I find it really interesting.

Biopsies may be taken during the procedures, watching this on the screen you see a claw type instrument that ‘grabs’ a section of the inside of the colon and pulls back to remove a tiny biopsy.  Though this isn’t painful, you can feel a little tug from inside which can feel odd.

The whole thing (depending on which scope you have) lasts between 10 and 40 minutes.  Afterwards, some recovery time is usually allowed to let the sedative wear off.  Most doctors require that patients have a person with them to help them home afterwards especially if you have had sedation.

One very common aftereffect is a bout of flatulence and minor wind pain caused by the air that is pumped into the colon during the procedure.  It can feel like you are really full up with wind and the only way to remove it is by passing wind.  You may have a little stomach ache afterwards or perhaps be sleepy after the sedation, it is good to rest for a day or so.

As with any medical procedure there are always the potential for complications, these aren’t common but could include; an adverse reaction to the sedative used during the exam, bleeding from the site where a tissue sample (biopsy) was taken or a polyp or other abnormal tissue was removed or a tear in the colon or rectum wall (perforation).  Your doctor will explain all the risks before you sign the consent form.

colonoscopy sigmoidoscopy

So there we go, I hope this post has helped answer a few questions.  Just remember that it’s a medical procedure, I know it can feel upsetting and embarrassing but it is necessary.  The idea of this blog came from me wanting to #StopPooBeingTaboo and this is why I feel it important to talk about these sorts of issues.  We are told that it is impolite to speak of body fluids and bottoms but it is the social embarrassment and fear that stop people seeking medical help.  The quicker you seek help, the better it is for your health.

If you have any more questions or other aspects of life with IBD that you would like me to post about, feel free to comment below or message me through my Facebook or twitter.

Sam xx



11 thoughts on “What happens during a colonoscopy?

  1. Dear Sam…THANK YOU!!
    I am having a colonoscopy in a few days time, and, I am beyond terrified. I’ve made myself sick with fear.
    Your article has made me a little more confident, and while I’m not looking forward to the procedure being done, I feel that I can cope with it.


    • Averil. iv had a few colonoscopys over the years its nothing to worry about you may feel a bit bloated when they pump air in but if its too uncomfortable just let the nurse know and the doctor will let air out it will be over in no time and you can watch it all on the tv screen if you like, and the best bit for me is I get a few days off work 🙂
      so don’t worry about a thing.
      all the best mike.


  2. Had 3 of these now,and wish the hospital had supplied your article.Its so true to my experiences.After the first one you sort of look forward to the next one as you have no worries about the procedure.


  3. I had one in November. It wasn’t as bad as I’d expected, but I did need sedative+gas and air, and still squeaked a bit when it got to the top. I think there is also water in the scope because it washes through at the same time. Your post is very instructive and reassuring, Sam. 🙂


  4. The memories of mine are like a dream, I’m not sure what was real and what isn’t! I remember being in pain even with sedative though.

    One thing I would mention is that if you have to travel to the hospital a fair bit after taking the epic laxative get yourself a hotel room near by as the laxative can still be working in the morning. That bit was not pleasant! ‘Moviprep’


  5. Hi Sam

    Thank you so much for this post. Just had my own 6 monthly routine visit to my Specialist for my Diabetes and was told I need to have a Colonoscopy and Gastroscopy as soon as possible.

    I’ve just written a post about my own (forthcoming) experience – see here: https://africandream01.wordpress.com/2015/06/25/stop-the-bus-i-want-to-get-off/

    Thank you for being such an inspiration and for your words of comfort and encouragement. I also love your sense of humour.


  6. Pingback: I heart colonoscopies- Tips and advice | The Morbus Crohnicles

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