What is a Sigmoidoscopy?
A Sigmoidoscopy is a test, which allows the Endoscopist to look
directly at the left side of the large bowel (Colon). In order to do
this, a flexible tube the thickness of a finger, is carefully passed
through the anus into the rectum and into the large bowel. This can
be uncomfortable as bends in the colon are negotiated and air is
used to inflate the colon. The Sigmoidoscope has a small camera
attached which is connected to a monitor system where images can
be seen.
Benefits
By examining your bowel the cause of your symptoms may be found.
Images and biopsies (samples) may be taken and sometimes polyps
(small growths in the bowel) can be removed or other treatments
performed.
Risks
A Sigmoidoscopy is a safe examination but rarely, a complication
such as bleeding or perforation may occur (1 in 1500, or if polyps
removed 1 in 200). Other risks are discomfort, bloating and pain.
Entonox® (gas and air) may cause nausea, dizziness and euphoria.
Sedation may cause nausea and vomiting, and rarely you may
become over sedated which can reduce your breathing rate.
Alternative treatments
There may be alternatives to this procedure and sometimes a
dedicated bowel CT scan is done instead. Your referring clinical
team have advised that this is the most appropriate test for you. If
you would like to discuss alternatives further please speak to the
clinical team on your ward.
What to expect on the day
The Endoscopy unit will coordinate with your ward team with regards
to special instructions prior to the procedure.
The Sigmoidoscopy may be undertaken after you have taken bowel
preparation, after administration of an enema or sometimes without
any preparation at all, depending on the indication for the procedure.
The Endoscopy Team will advise the clinical team on your ward
accordingly.
In order for the test to be successful it is important that you take any
bowel preparation or have an enema if required as instructed by
the clinical team on the ward and that you follow instructions with
regards to any special diet or clear fluids until the Sigmoidoscopy.
Before the procedure an Endoscopy Nurse will explain the test and
ask you some health questions. They will answer any questions or
concerns you may have.
You will be asked to sign a consent form.
A cannula will have been inserted in preparation for your procedure
(a small plastic tube).
We will transfer you to the Endoscopy Unit. You may have to wait for
some time until the procedure room is available. When it is your turn,
you will be taken into the procedure room for your test.
In the endoscopy room the procedure will start with you lying on your
left side on a trolley. You may be asked to change position during the
procedure.
Please be aware we are a Teaching Hospital and may have trainees
in any areas of your pathway. They will always be supervised and
they will always be working at an appropriate level for their training
stage. If you would rather not have a trainee involved in your care
please let the staff know your wishes. This will not affect your care.
Sigmoidoscopy with Entonox
If you are having Entonox® (gas and air) instructions will be given on
how to self administer this before your Sigmoidoscopy starts.
Entonox® is inhaled through a mouthpiece to relieve pain.
A cannula (small plastic tube) may be inserted just in case any
medication is needed during your Sigmoidoscopy.
After the procedure you will be transferred to our recovery area and
then subsequently back to your ward. The Sigmoidoscopy result will
be communicated to you by the clinical team on the ward.
Recovery from the effects of Entonox® is rapid.
You may feel bloated with wind-like discomfort. This is normal and
usually settles quickly. If you have a biopsy taken or a polyp removed
it is common to pass small spots of blood from your bottom for a day
or two following the procedure.
Sigmoidoscopy with Sedation
You will need a cannula (small plastic tube) in your hand or arm
through which a mild sedation and analgesia (pain relief) is given.
This should relax you but will not put you to sleep. It is not a
general anaesthetic.
You will be awake and aware during the procedure with sedation.
Sedation may cause loss of memory and judgement for 24
hours after the test. You must not:
• Drive
• Drink alcohol
• Operate machinery
• Sign legal documents
If you are discharged from the ward within 24 hours of your
procedure you will need someone to accompany you home and
to remain with you overnight as the effects of the sedation will
still be in your system.
After the procedure you will be transferred to our recovery area and
then subsequently back to your ward. The Sigmoidoscopy result will
be communicated to you by the clinical team on the ward.
You may feel bloated with wind-like discomfort. This is normal and
usually settles quickly. If you have a biopsy taken or a polyp removed
it is common to pass small spots of blood from your bottom for a day
or two following the procedure.
Frequently asked questions
How long will the procedure take?
A Sigmoidoscopy lasts between 15 and 20 minutes.
Does it hurt?
Sometimes patients find the test painful but gas and air (Entonox®) or
sedation is available to use for pain relief if needed.
Do I have to have the test?
No. The choice is yours, please refer to page 3 for alternatives and
the reason why this test is appropriate.
Can I take my tablets as normal?
Please take medications before and after the procedure as
instructed by the clinical team on your ward.
Will I be asleep for the procedure?
No. Gas and air (Entonox®) or sedation is available (if your
circumstances permit), but you will be awake throughout the
procedure.
Procedure Outcome
After the procedure you will be transferred to our recovery area and
then subsequently back to your ward. The Gastroscopy result will
be communicated to you by your clinical team on the ward. Biopsy
results will be communicated by your referring clinician at a later
date.
Sigmoidoscopy Illustration
Access from the main hospital multistorey car park
We are located in Area 6 - Gastroenterology & Endoscopy Unit,
highlighted in orange on the main hospital map. Follow the signs for the
Main Hospital up the escalator/lift towards Area 6, second corridor on the
left. Follow the signs down the link corridor, exit to the right via the side
door (external) which is signposted for Patient Entrance to Reception.
Access for drop off/collection only & disability parking
Enter via East Park Drive and follow the road up the hill, take the
second left signposted for Gastroenterology & Endoscopy Unit Drop
Off Only, follow the road round to the right.
We are aware this PDF are might not be accessible to all users. If you would like to request an accessible version, please contact bfwh.
Read our accessibility statement to learn more.
Author Gastroenterology & Endoscopy Unit
Approved by EUG Meeting
Date of Publication 18/02/2026
Reference No PL/907 (V4)
Review Date 01/02/2029
