Contact us
General enquiries 020 7806 4000
Urgent care clinic 020 7432 8300
Book an appointment 020 7806 4060


A sigmoidoscopy is a minimally invasive procedure that examines the rectum (where your poo collects before it comes out) and the lower part of the colon closest to the rectum (the sigmoid colon and descending colon).

Also known as… flexible sigmoidoscopy or rigid sigmoidoscopy – depending on the instruments used. A rigid sigmoidoscopy can also be called a proctoscopy.

Contact GI Clinic

What is a sigmoidoscopy?

A sigmoidoscopy is a minimally invasive procedure that examines the rectum (where your poo collects before it comes out) and the lower part of the colon closest to the rectum (the sigmoid colon and descending colon). Unlike a colonoscopy, which examines the entire colon (the large bowel), a sigmoidoscopy focuses on the lower sections.

A sigmoidoscopy allows doctors to identify:

  • Inflammation in your intestinal lining (colitis or proctitis)
  • Infected pockets in your intestinal lining (diverticulitis)
  • Scar tissue that is narrowing your intestine
  • Ulcers
  • Gastrointestinal bleeding
  • Polyps (benign or cancerous growths on the lining of the intestine. These can often be removed during a sigmoidoscopy.)
  • Colorectal cancer (also known as colon cancer)
  • Rectal cancer

A sigmoidoscopy may be recommended if you are experiencing these symptoms:

  • Bright or fresh rectal bleeding
  • General or non-specific tummy symptoms
  • Belly pain
  • Feeling bloated

A sigmoidoscopy involves using a thin tube with a light and camera at the end. This can be flexible or rigid. During the procedure, your doctor may also perform a biopsy, where tissue samples are taken to help make a diagnosis, or remove polpys, which are very common growths in the intestinal lining. Haemorrhoids (piles) can also be checked and treated during a sigmoidoscopy.

The difference between a flexible sigmoidoscopy and a rigid sigmoidoscopy

A flexible sigmoidoscopy examines the rectum, sigmoid colon and descending colon, using a long, thin flexible tube.

A rigid sigmoidoscopy uses a shorter rigid tube (proctoscope) to examine only the rectum and sigmoid colon.


If you are worried about your bowel symptoms and would like to see a consultant, get in touch and we will book you in with one of our specialist doctors.

During this appointment, your doctor will ask about your symptoms, any test results, and take a detailed medical history. If you have paper copies of previous test results or treatment plans, please bring these with you. After this, they will talk through your options and let you know whether you should have additional tests, such as bloods or a poo sample.

This appointment will also help determine whether a sigmoidoscopy or colonoscopy should be performed.

Make sure to tell your doctor if you are taking any medications — especially for diabetes, high blood pressure or heart problems, take medications or supplements that contain iron, or are on blood thinners, such as warfarin or aspirin, as you may need to adjust your dosages or stop taking them temporarily ahead of your sigmoidoscopy. You should only change your medication intake if your doctor has advised you to.

If you decide to have a sigmoidoscopy, a few days before, our Pre-Assessment team will call you to explain what will happen on the day and answer any questions you may have.

Preparing for the procedure

Your lower bowel will need to be clear of residue for your sigmoidoscopy so that your doctor can conduct a thorough exam. Your doctor will give you specific instructions to help you prepare for the procedure, such as:

  • Seven days before. If you take iron supplements, stop taking these.
  • The day before. If you are having a flexible sigmoidoscopy, you may need to follow a low fibre diet or fast the day before. Drinks may also be limited to clear liquids, such as water and black tea or coffee. Avoid red drinks which could be mistaken for blood during the test. You may also need to take a laxative the night before to help clear your bowel. If you are having a rigid sigmoidoscopy, you can eat and drink as normal the day before.
  • A couple of hours before. If you are having a flexible sigmoidoscopy, you will need to use an enema before leaving for your appointment. This will help make sure the area of your bowel being examined is empty. This is simple and easy to use. Once you have done the enema, you should not have anything else to eat or drink. You will be given instructions that will guide you through the enema process. If you are having a rigid sigmoidoscopy, you will need to use some suppositories that will help empty your rectum before leaving home. These simply need to be inserted into your back passage and held in place for at least 20 minutes.

When you arrive at our hospital, we will show you to your room and you will change into a hospital gown. Don’t forget to bring any prescription medications with you! Then, your doctor will see you before your procedure and check that you’re still happy to go ahead.


Flexible sigmoidoscopy

This is a quick procedure and should only take around 15 minutes, though it might take a little longer if you have a treatment or biopsies taken. We recommend being sedated as this will relax you and reduce discomfort. However, if you have sedation, you will need to be collected and taken home as you will not be able to drive.

Once you are comfortable, your doctor will start. There are two common positions for the test: lying on your left side with knees hugged into your chest or kneeling on your knees and leaning forward. Once you are in place, your doctor will gently insert the tube into your bottom using a medical-grade lubricant. Air will also be pumped into the large bowel to open it up and make the lining easier to see. As the tube passes through your bowel, the camera will send video to a screen, so your doctor can inspect the health of your large bowel and see if there are any areas that need a closer look.

If your doctor notices polyps, they can remove these. Don’t worry – this is painless. If the polyps are large or in an awkward location, these may need to be removed surgically at a later date. If active bleeding is found, this can also be treated during the procedure, saving you another trip to hospital.

Rigid sigmoidoscopy

This is a very similar procedure, but sedation is usually not needed. Your doctor will start by conducting a rectal exam with a gloved lubricated finger and will then gently insert the proctoscope. As the proctoscope moves up through the bowel, air is pumped in to open it up. The procedure should be uncomfortable but not painful. As above, images will be sent to a screen so your doctor can take a look at your rectum and lower colon’s health. If needed, biopsies will be taken. You should not feel this being done. The test should take 5 – 15 minutes. During and after the test, it’s normal to feel and hear air escaping from your back passage. This is totally normal so please don’t be embarrassed.


After your procedure, you will be taken back to your private room, where our nurses will do some checks and make sure you feel ok. It’s normal to feel a little uncomfortable and gassy due to the air that was used. Letting this out will help minimise any discomfort.

Once you’re settled, we’ll give you a procedure report and your doctor will inform you of the next steps. If you had biopsies taken, the results will usually be ready after one week.

If your results suggest you need a follow-up appointment, our team will let you know before you leave hospital so you can book this in.

If you had sedation, you should be picked up and looked after for the next 24 hours while it wears off. During this time you should not drink alcohol, cook or make important decisions.

If you have cramps when you get home, don’t worry – this is very normal.

You may also experience:

  • Bloating
  • Excess wind
  • A little bleeding

If you experience more severe symptoms, such as:

  • Severe tummy (abdominal) pain
  • Bloody bowel movements, rectal bleeding or blood clots
  • Raised temperature (fever)
  • Vomiting

Please call our Urgent Care Clinic for advice, or head to A&E – take your endoscopy report with you.

How to pay for your treatment

If you’re… paying for yourself

Did you know you don’t need private medical insurance to come to St John & St Elizabeth Hospital? As a self-pay patient, you can access safe, outstanding quality health care at times to suit you.

For scans and tests, as well as to see most consultants, you’ll still need to be referred by a medical professional like your GP, but as a self-pay patient, the process is more straightforward. You won’t need authorisation from an insurance provider, and you’ll have greater choice of consultant and appointment times.

If you’re… insured

St John & St Elizabeth Hospital is approved by all major medical insurance companies. If you have a personal private health insurance policy, or your company provide it for you, you can use it to pay for your care from your initial consultation through to treatment, surgery and aftercare such as physiotherapy. Not all private health insurance plans cover the same things. It’s very important to check exactly what you are covered for with your insurance provider.