Flexible sigmoidoscopy

Our world-leading gastroenterologists and expert nursing team provide a first-class flexible sigmoidoscopy service to diagnose and monitor conditions of the large bowel.


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Quick facts

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What is it for?

For the diagnosis of large bowel diseases


A flexible sigmoidoscopy involves a long, thin, flexible tube (sigmoidoscope) being inserted into your anus and gently passed into the lower part of your large bowel (also called the large intestine or colon). 

At the end of the tube are a camera and light that allow your consultant to view bowel conditions that already exist or look for anything that doesn’t look right.

For example, a flexible sigmoidoscope is often used to look around the large bowel for early signs of colorectal cancer. 

Your consultant can also attach tiny surgical instruments to the end of the tube to take samples of body tissue (a biopsy) or remove small polyps (small clumps of cells). 

Compared to a colonoscopy, a sigmoidoscopy does take less time and there are fewer risks involved. 

However, a colonoscopy allows your consultant to view your whole colon, rather than just the lower part of it.  

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Why choose The London Clinic

Excellence in one place

We operate as teams of experts with world-class resources dedicated to maintaining the highest standards of medical care. You are surrounded by the latest treatments and advice with everything you need to get back to your best health.

Personal care, every time

Exceptional patient care is a way of life for us. Our nurses, clinicians and support teams are dedicated to the care of a very small number of patients, so have more time for you. They’ll be with you every step of the way, tailoring your care around you and giving the peace-of-mind that comes with knowing you’re in the best hands.

Effortlessly simple

We work together as one to guide you through each step of your experience, with complexities unravelled and answers readily to hand. Your personal treatment plan will be laid out for you, with all the details taken care of so you can focus on you.

What's included in your package?

Choosing The London Clinic means your treatment plan will be laid out for you, with all the details taken care of so you can focus on you.


Your treatment package will include:

  • Enhanced pre-admission assessment
  • Your treatment with our complete care team at your fingertips
  • Personalised aftercare and follow-up

We want you to be in control of your health. That’s why we also offer optional services such as comprehensive recovery packages and extra touches for you to choose from during your stay with us.

How to pay

  • You can use private medical insurance (PMI) to access this treatment. We work with all major PMI providers in the UK and many internationally
  • You can pay for yourself (self-pay)
  • If you’re paying for yourself, we have finance options available with Chrysalis


Your consultant may recommend a flexible sigmoidoscopy if your bowel habit has changed. 

Investigation is important for people with symptoms that include:

  • Bleeding or mucus from your back passage, or blood in your poo
  • A change from your usual bowel habit, for example, your poo is looser than normal or you’ve recently become constipated
  • Decreased appetite
  • Weight loss
  • Tiredness
  • Abdominal pain, which may get worse after you eat
  • Bloating
  • An abdominal lump or swelling

Our expert gastroenterologists use a flexible sigmoidoscopy to diagnose inflammatory bowel disease, remove polyps and check for evidence of colorectal cancer.

Colorectal cancer affects as many as 1 in 20 people during their lifetime. 

Most colorectal cancers develop from small, slow-growing growths called polyps. 

They are found in 1 in 10 people aged over 50. Most polyps are harmless, but some may contain abnormal cells or cells that may turn into cancer. 

Regular screening for colon cancer is the best way to protect yourself from the illness.

If bowel problems and colorectal cancer are diagnosed at an early stage, your treatment will be more effective. 

Your world-leading gastroenterologist will perform your flexible sigmoidoscopy as an outpatient procedure. 

This usually means you won’t need any medication to make you feel calmer or reduce discomfort. 

However, if you are worried about the procedure, we’ll offer you medication to help you feel more relaxed, such as a sedative.

During your sigmoidoscopy, you’ll lie on your side on an examination couch, with your knees drawn up towards your chest. 

Your consultant will squeeze some liquid or gel into your back passage that allows for smooth movement. They will then insert a long, thin, flexible tube (sigmoidoscope) into your anus and gently pass it into your colon.

They may also pass air or water into your bowel to make sure they get the clearest view possible. A camera at the end of the sigmoidoscope sends high-quality images of the gut to a computer screen. 

Your consultant looks at the screen during the investigation to pick up on anything that may need to be looked at further.

During your sigmoidoscopy, your gastroenterologist may also use tiny surgical instruments at the end of the tube to take body tissue samples (biopsies) or remove small polyps (small clumps of cells). 

A flexible sigmoidoscopy usually lasts less than 10 minutes, but will depend on whether they take a biopsy or need to remove a polyp.

Before your flexible sigmoidoscopy, you'll need to empty your large bowel. This is because any waste in it may stop your consultant from getting clear views of your colon and rectum.

To empty your bowel, you may be asked to:

  • Follow a special diet the day before your procedure 
  • Take a pill or medicine, such as a laxative, the night before your procedure 
  • Use an enema kit, where you insert a liquid through your anus to clear out your back passage 

If you normally take medication or supplements, your care team will also discuss with you if you need to stop taking these and the best times to do so.

After your flexible sigmoidoscopy, you’ll recover in our calming and comfortable Endoscopy Unit until you feel ready to go home. 

You may feel a little bloated or experience some cramping pain after your sigmoidoscopy. This may be the result of gas passed into your bowel. It usually settles down in a few hours. 

Your nursing team will offer you painkillers to ease any discomfort and discuss other possible side effects you may experience at home. 

This includes a small amount of blood in your first poo after your sigmoidoscopy, which usually isn’t anything to worry about.

You should be able to return to work and normal activities the next day. And if you do have any questions or concerns, you can contact your care team at any time.

Our world-leading gastroenterologists and experienced nursing team will work closely together to reduce any risk and support your safe recovery. 

Rarely, problems caused by a flexible sigmoidoscopy include: 


This is more likely to happen if body tissue or a polyp is removed during the procedure. The bleeding usually stops naturally, but your consultant may also stop it by burning (cauterising) the tissue that’s bleeding.

Tear in the bowel wall

This risk is higher if a polyp is removed.

Your consultant will be able to discuss what they have seen during your flexible sigmoidoscopy as soon as you feel able to chat. 

They may also arrange an appointment to discuss the results of tests carried out on any body tissue removed during your procedure. 

These results are usually available in three to four working days. 

At this appointment, your consultant will also explain your diagnosis, discuss your treatment options and chat through any worries you may have.


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