Flexible Sigmoidoscopy

This section of the wesbite details what a flexi sigmoidoscopy is, and provides information for patients preparing for the procedure. This informationon on Flexible Sigmoidoscopy is available in an alternative format.

What is flexible sigmoidoscopy?

In this examination the doctor uses an instrument called a “flexible sigmoidoscope” this is a long flexible tube, about the thickness of your index finger, with a bright light at the end, which allows examination of the lining of the large bowel. A clear view of the lining of the bowel enables the doctor / nurse to check whether or not any disease is present. Polyps may also be seen. Polyps are abnormal projections of tissue, rather like warts, and it is possible to remove them during Sigmoidoscopy, this is quite painless. Sometimes the doctor takes a biopsy – a sample of the lining for examination in the laboratory. A small piece of tissue is removed painlessly through the Sigmoidoscope using tiny forceps.

The flexible sigmoidoscopy will be performed with you lying on your left side with your legs in a curled position. The sigmoidoscope has a lens and a light source that permits the endoscopist to look at a television monitor where the image is magnified many times so the endoscopist can see minute changes in tissue.

The endoscope contains channels that allow the endoscopist to take biopsies (small pieces of tissue) and to introduce or withdraw fluid or air. Biopsies do not hurt; the lining of the colon does not have that type of pain sensation. However, you may experience some cramping as air is introduced through the scope and the scope is passed through twisty segments of the colon. The air is needed to permit the endoscopist to advance the scope and see the lining of the colon. Do not be embarrassed about releasing the air through your rectum. Let the endoscopist know if you are uncomfortable since air can also be removed through the scope.


You will be offered sedation for the test but the procedure is brief and the discomfort mild so you may feel you do not need it. Sedation involves giving you an injection that will make you relaxed and sleepy during the investigation. If you have the sedation you will have to bring an escort with you for the procedure. They must remain in the department while you are having your gastroscopy and then your escort must take you home after the procedure. The escort does not come into the endoscopy room while you have your procedure done.

Before the procedure:

To allow a clear view the lower bowel must be completely empty of waste material; there are two methods for this and your doctor will advise you which you should have.


The Enema will be sent to you at home with instructions for use (these are also set out below). The enema should be used approximately 1 hour before the test is due. If you are unable to administer the enema at home it will be possible to have the enema on arrival in the department with help from the nursing staff.


You will be required to drink 2 sachets of liquid bowel preparation to clear the bowel the day before the procedure and drink plenty of fluid. You may experience abdominal pain or a headache, in which case it is fine to take paracetamol or similar analgesia.

Medicines and Medical Conditions

It is important you bring a list of your current medication with you so that you can give it to the nurse on arrival.

Iron tablets

If you are taking iron tablets please stop taking them for TWO WEEKS BEFORE the procedure. This is because iron coats the colon, making it difficult to see the lining.


If you are taking Aspirin please stop taking this 7 DAYS before the procedure. This is because Aspirin makes you more likely to bleed


If you are taking Warfarin tablets, please inform the Gastroenterology Unit as soon as possible, as our doctors may decide that it is necessary for you to stop taking your tablets for a limited time before the gastroscopy.


If you suffer from diabetes, please inform the Gastroenterology Unit as soon as possible, as it may be necessary to change the time of your appointment or be admitted to hospital a day before your procedure for treatment. If your diabetes is managed by your GP please contact the surgery for advice. If under the care of Elsie Bertram Diabetes Centre, please contact your Diabetes specialist nurse on 01603 288513.


If you are pregnant or breast-feeding please contact the Gastroenterology Unit 01603 288169.


When you come to the department, the procedure will be explained and a doctor will ask you to sign a consent form. This is to ensure you understand the test and its implications / risks. If you have any worries or questions at this stage don’t be afraid to ask. The staff will want you to be as relaxed as possible for the test and will not mind answering your queries.

After the Procedure

The endoscopist will talk to you at the end of the procedure, explaining what has been found. However, if a biopsy has been taken the results may take several days. Details of the results and any necessary treatment will be sent to your GP or a further outpatient appointment may be necessary.

You will be left to rest as you may feel sleepy if you have had sedation. If you chose to have sedation it is a good idea for the person taking you home to be with your when you speak to the endoscopist. If sedation has been used, people find they forget what has been said and may not even recollect having the test at all.

Returning Home or Back to the Ward

Once you have returned home, or back to your ward you may begin to eat and drink normally and resume your normal medication, unless instructed otherwise by the Doctor.

If you have had sedation you must have someone to escort you home and stay with you for the 24 hours after your test.

Following sedation you must not do any of the following for 24 hours:

  • Drive a motor vehicle
  • Drink alcolhol
  • Operate machinery
  • Sign legal documents

Side Effects

Side effects of this procedure are usually minimal. Sometimes patients may experience abdominal pain due to air introduced into the colon. Also it is not unusual to experience some diarrhoea for a couple of days post procedure until the bowel returns to its normal function. You will be given an advice sheet on after care and signs to watch for when you have had your procedure.

Risks and Complications

The main risks of flexible sigmoidoscopy are damage to or perforation of the colon during the procedure. This can lead to bleeding and infection, which may require treatment with medicines or surgery.

Useful sources of information

Additional information can be found at these websites:

Ref: CDD Leeds: Patients Guide to Flexible Sigmoidoscopy (Dec 2001 rev Sep 2006)

  • Do not eat for at least 30 minutes before using the enema
  • Do not eat after using the enema until after you have had the test
  • You may drink any soft drinks, tea or coffee
  • You should use the enema even if you have recently passed a motion
  • Unscrew lid of bottle
  • Connect enclosed tube to bottle
  • Smear the lubricating jelly on the nozzle (first inch)
  • Lie on your left side on a towel
  • Gently insert nozzle (about 3 inches) into your bottom
  • Squeeze the contents in, remove the nozzle and continue lying down
  • Try to hold the liquid for at least 5 mins – the longer the better
  • Go to the toilet but do not worry if you do not pass a motion
  • Some people may experience m
    ild stomach cramps for a short while
  • Some people feel faint or dizzy please lie down until you feel better

Most people find it comfortable to use the enema at home. If you feel you cannot do it yourself please contact the unit and we will arrange for you to have it done in hospital on arrival

Ref. CDD Leeds: Patient guide to colonoscopy (January 2003 rev Sep 2006)