A flexible sigmoidoscopy is a procedure to look inside the lower part of your large intestines (colon) – your descending colon, sigmoid colon and rectum. Your colon leads from your small intestine to your rectum and the sigmoid colon is the section of colon just before your rectum.
A flexible sigmoidoscopy is a type of endoscopy, which involves inserting a thin, flexible instrument called a sigmoidoscope into your rectum. The sigmoidoscope has a light and a tiny camera at the end that produces video images of the inside of your colon. If necessary, tissue samples (biopsies) can be collected via the sigmoidoscope.
Preparing for your flexible sigmoidoscopy
Even if your GP has referred you for a flexible sigmoidoscopy, your first appointment will be with one of our Pre-Assessment Nurses. This assessment ensures the procedure is clinically appropriate and that you are safely prepared.
We aim to offer timely access to care, with appointments available at a convenient time for you.
What to expect at your pre-assessment appointment
During this appointment, the pre-assessment Nurse will review your medical history in detail and discuss your current health. This will include:
- Any existing medical conditions
- Your current symptoms, including frequency and severity
- Previous investigations or treatments
- A review of your medications and any allergies
Basic observations such as blood pressure and pulse may be taken to ensure you are fit for the procedure. The nurse will explain the flexible sigmoidoscopy, including how it is performed, any potential risks, and answer any questions you may have.
Your healthcare team will also give you a detailed explanation of how to prepare for the procedure, including what to eat and drink in the days beforehand and any bowel preparation that needs to be done.
If needed, your case will be reviewed by a consultant gastroenterologist, who will oversee your care and confirm the plan for investigation.
Ongoing support
After your pre-assessment, our team will provide clear instructions for bowel preparation and confirm your procedure date. We are committed to ensuring you feel informed and supported throughout your care journey.
Choosing the correct bowel preparation guidance
At the bottom of this page, you will find links to guidance on your bowel preparation. It is important that you read and follow the link that matches the bowel preparation you have been prescribed, as advised by your pre-assessment nurse.
Some preparations may look similar but have different instructions. Please do not use a preparation that is not intended for you.
If you have any questions, please contact the endoscopy team on 0203 058 9083 or 0203 058 9068 for further clarification.
What happens during a flexible sigmoidoscopy
A flexible sigmoidoscopy usually takes 10–20 minutes, although the exact time can vary depending on the patient. Most people do not need a general anaesthetic, but if appropriate, your endoscopist may offer a sedative or gas & air to help you relax. Any options and associated risks will be discussed with you beforehand.
The procedure is usually carried out by an endoscopist. You will be asked to lie on a table, typically on your left side.
The endoscopist will gently insert a thin, flexible tube (colonoscope) into your anus and slowly guide it into your lower colon. Air may be introduced to expand the colon slightly, giving a clearer view of the lining.
During the procedure, your endoscopist can:
- Take biopsies (small tissue samples) for testing
- Remove certain polyps
- Take photographs to aid diagnosis
Any tissue samples or polyps removed will be sent for analysis, and your endoscopist will discuss the results and next steps with you as appropriate.
Recovery after a flexible sigmoidoscopy
A flexible sigmoidoscopy is a minor, day-case procedure, and most people recover quickly.
You may feel slightly bloated or have mild abdominal cramping for a few hours, and it is possible to notice a small amount of blood in your first bowel movement. Your healthcare team will explain the findings and discuss any treatment or follow-up that may be needed.
Most people can return to normal activities immediately and resume work the following day. If a sedative was used, its effects may last up to 24 hours, so you will need someone to accompany you home and should avoid driving, alcohol, or operating machinery during this time. Clear instructions will be provided by your healthcare team before your procedure.