Important information
Please read all of this leaflet or you may miss important information about your test. If you do not follow the instructions we may need to cancel your test on the day.
What is flexible sigmoidoscopy?
A flexible sigmoidoscopy looks at the lower part of your large bowel (colon). Many patients choose to have Entonox (gas and air) during the procedure or take nothing at all. Some may prefer to have a light sedative.
How long will the sigmoidoscopy procedure take?
It takes around 10 to 20 minutes. In some cases this may be longer, but this does not mean anything is wrong. You should expect to be in the department 2 to 4 hours. Unfortunately, it may not always be possible to run on time. The staff will try to keep you informed.
Why do I need to have a sigmoidoscopy?
To help your doctor find the cause of your symptoms by looking directly at the lining of the colon. There are many reasons for this investigation including bleeding from the bottom, abdominal (tummy) pain, to look further at findings from another scan or X-ray, or surveillance of an existing condition.
During this test the endoscopist may take a biopsy (small sample of tissue) for testing, or remove polyps if appropriate. The tissue is removed through the endoscope using tiny forceps and does not hurt.
What are the benefits of this procedure?
To help diagnose and/or treat your condition. It may also help your doctor decide if any further investigations are required.
What if I do not have the sigmoidoscopy or change my mind?
It may be difficult to diagnose your condition or offer suitable treatment. You may find it helpful to discuss the test with your GP or referring doctor. If you decide not to go ahead, please let us know.
Can I seek a second opinion?
Yes, please seek advice from your GP or referring consultant.
Is there an alternative to a sigmoidoscopy?
A CT colonogram is an alternative to a sigmoidoscopy but samples cannot be taken during this. So if an abnormality is found, you may need an endoscopy after that.
What are the risks?
Bleeding: may occur at the site of biopsy or polyp removal (risk of less than 1 in 1000 examinations where this is performed). This usually isn’t too serious and bleeding may stop on its own. If it does not, it can be controlled by cauterization or injection treatment.
Perforation: (or tear in the bowel lining) the risk is approximately 1 for every 15,000.
Reaction to medication: if you choose to have sedation, this may cause a problem with breathing, heart rate, or blood pressure. You will be monitored during the procedure to look out for this. Medication to reverse the sedation is available and we will support you as needed.
Missed diagnoses: there is a very small risk that the colonoscopy misses an abnormality due to small folds in the lining of the digestive tract. In these areas the views may be less clear.
Pain: most people can cope well with this procedure. It is common to experience discomfort for a short time, however, a small number of patients may have some pain.
Failure to complete the procedure: your comfort and safety are our priority, we will stop at any time if we cannot ensure this, or if there is a problem with equipment (this is rarer).
What preparation is required for my sigmoidoscopy?
The left side of the bowel needs to be empty so we can see it clearly. You will be given one of the following:
- bowel preparation for you to take the day before the test
- an enema for you to do yourself at home, 2 hours before your appointment
Sometimes the enema is done on the unit by the endoscopy nurses. We will give you detailed instructions.
You may have been offered a pre-assessment telephone call to cover any questions you may have, if not please contact the helpline on: 0117 414 5077.
If you choose to have sedation, please make sure a responsible adult is available to collect you from the department and stay with you for at least 6 hours. Make sure you bring their contact details so we can let them know you are ready to be collected.
What about my medication?
You should take all your usual medication at the normal times with small sips of water unless you have been advised not to. Some medications need to be stopped or adjusted 1 to 2 weeks before your appointment.
Please notify the department as soon as possible if you:
- have diabetes
- take medication to thin your blood/prevent clotting like warfarin, apixaban, rivaroxaban, dabigatran, edoxaban, clopidogrel
- take long term steroids
- take iron tablets
- take weight loss injections
Why have I been asked if I have a pacemaker/internal cardiac defibrillator?
Implanted permanent pacemakers or cardiac defibrillators can be affected by electrical interference which may happen during sigmoidoscopy. We can take precautions as long as you tell us before the procedure. Please notify the department if you have one.
Do I need to bring anything with me?
A list of your medications and any you may need to take while you are in the department, such as insulin, inhalers, or GTN spray.
A dressing gown and slippers, if you have them. You are advised not to bring valuables with you. Your belongings will stay with you throughout your stay.
What happens when I arrive?
Please speak to the receptionist. They will check your details and may ask you to complete a form with details of your medical history, and contact details of your next of kin and the person collecting you.
We ask your family and friends not to accompany you beyond this point. The department can be very busy and space is limited. We will tell them the approximate time that you will be ready. The recovery staff will call them with a time they can collect you.
The nurse will take you to an admission room to complete the paperwork, check your blood pressure, pulse, and oxygen levels to make sure you are well enough to have the procedure. If you have diabetes the nurse may also test your blood glucose level.
If you decide to have sedation, a cannula (flexible needle) will be inserted into a vein in the back of your hand or arm so that the intravenous sedation can be given.
The nurse will discuss the risks and benefits of having the procedure to make sure you understand what the procedure involves. You will be asked to sign the consent form. You will be able to ask questions at this point.
Will I have sedation?
The sigmoidoscopy can be slightly uncomfortable but hopefully not painful. Many patients do not require sedation ban choose to have Entonox (gas and air) instead. This leaves the body after 30 minutes so you can leave the unit shortly after the procedure alone and carry on as normal.
If you choose to have sedation, a cannula will be inserted in a vein in the back of your hand or arm. The sedation will make you drowsy but not unconscious. You will still hear what is being said to you. It is not a general anaesthetic. You will need to arrange for someone to collect you from the unit and stay with you for at least 6 hours.
Your reaction times will be slower and your judgement impaired. You will not be able to drive, operate heavy machinery, sign any legally binding documents, or look after small children or vulnerable adults for 24 hours.
Can my relative/friend stay with me?
There is limited space within the department so unfortunately this is not possible. We will advise them of an approximate time for you to be collected.
Will I be in a mixed ward?
There are separate male/female waiting and recovery areas.
Who will be in the procedure room with me?
- A nurse who will monitor and support you.
- The endoscopist who will do the procedure.
- Another nurse who will assist the endoscopist.
The procedure will be done by a consultant or a non-medical/ clinical endoscopist. In some cases, an endoscopist who is doing further training (a qualified professional) may also be there. They will be learning to perform endoscopy under direct, expert supervision.
If you would prefer not to have your sigmoidoscopy done by someone training, you can tell us before coming into the procedure room.
Student nurses may also be there and be supervised by the training nursing staff.
What can I expect during the procedure?
When you enter the room, you will be introduced to the team. A checklist will be completed and you will be asked to confirm your details. This is standard procedure to ensure your safety.
You will be made comfortable on a trolley and any monitoring equipment attached. The nurse looking after you will be at your head throughout.
If you are having sedation this will be given through the cannula in the back of your hand or arm. Once you are relaxed the procedure will begin. The endoscopist will do a rectal examination before passing the endoscope into your bottom.
The endoscopist will inflate the bowel with air or water. This may be uncomfortable but it will pass.
What happens after the procedure?
You will be taken into the recovery area. If you have sedation you will be monitored. When you have recovered the staff will contact your relative/friend to tell them when you will be ready to go home. You will be given written discharge advice and cannula removed if you’ve had sedation.
If you have had Entonox, once the effects have worn off you will be allowed to leave the unit on your own.
In both cases you will be offered refreshments.
When do I find out the results?
Before you leave the department the results of will be explained to you together with any further tests that may be required.
Biopsies usually take at least 4 weeks to be processed, sometimes longer. You will be told the results by letter or at an outpatient appointment.
How will I feel after the sigmoidoscopy?
You may feel bloated due to air still in your bowel but this should soon settle. If you have had biopsies or polyps removed a small amount of blood may be present when you go to the toilet (poo).
What should I do when I get home?
If you have had Entonox you can return to your normal day as soon as you feel able.
If you have had sedation, rest quietly for the rest of the day. You will be able to return to normal activities after 24 hours.
You will be given detailed discharge advice before you leave the unit.
What if I feel unwell or have any concerns after I have been discharged?
If you have any of the following please contact your GP, NHS 111, or go to the Emergency Department and take your results with you:
- a fever
- passing a lot of blood from your bottom or black stools (poo)
- severe abdominal pain
- severe bloating or vomiting
A copy of your results is sent to your GP. You will also be given a copy in case you need to seek medical advice before your GP receives their copy.
If you have any concerns about your test please contact the helpline. Leave your name, number and a short message: 0117 414 5077.
Date published: 18 March 2026 Review due: 31 March 2029 PI number: BFT002232