Please read this information as soon as you receive your appointment.

This information has been prepared to enable you to make an informed decision when you are asked to give consent to the procedure / investigation. If you find you have any questions or concerns, please contact the Day Surgery Unit on 01935 384 339 and speak to the endoscopy sister, or you can speak to the nurse or endoscopist on the day.

What is a colonoscopy?

A colonoscopy is an examination of the large bowel (colon). It is carried out with an instrument called a colonoscope. This is a narrow, flexible tube with a light and a camera in its tip.

You have been sent a bowel preparation. It is important that you follow the instructions in the leaflet exactly, as the success of the examination depends on you doing so. The Endoscopist can only view the bowel properly if it is completely cleared. Failure may mean we have to repeat the procedure at a later date.

Your GP will arrange a set of blood tests prior to your appointment.

If you have had a heart attack, have a PPM or ICD, have had a stroke or serious injury, or had change in your kidney function in the last six weeks please telephone the department on 01935 384339 before taking your bowel preparation

Diet before the examination

  • Follow the low residue diet advice given in the enclosed bowel prep for two days prior to your appointment. 
  • Follow the instructions given with the bowel cleansing solution depending on whether you have a morning or afternoon appointment
  • Drink plenty of clear fluids eg. water, black tea and coffee or fruit juices. Avoid red wine and blackcurrant juice
  • It is important not to eat after starting your bowel preparation as this can obscure the view the endoscopist has of your bowel and something important could be missed
  • If you have been told you are having a gastroscopy (examination of the stomach) at the same time as your colonoscopy, please STOP having fluids to drink four hours before your appointment time, otherwise continue to drink plenty of fluids until right up to your appointment.

If you have diabetes and are on insulin, you need to contact the Diabetes Nurse Specialist on 01935 38 4517 for advice. Stop Metformin and oral hypoglycaemia tablets at the same time as starting bowel preparation. Restart the day after the procedure unless directed by the diabetes specialist nurse.

If you take tablets for your diabetes

The necessary changes to your food intake may upset your diabetes control. You may on the day of the test be at risk of having low blood sugar or “hypo”, so make sure that the sugary drinks are taken as advised below. The following clear fluids may be taken freely during the day (avoid blackcurrant juice):

  • Water
  • Black tea/coffee
  • Sugar-free or diet cola, lemonade or squash (avoid blackcurrant juice as per the diet sheet above)
  • Sugar-free jelly

It is important that you continue to take carbohydrates as part of your diet in order to prevent “hypo”. You will need approximately 20g of carbohydrate as sugary drinks every two to three hours. 

  • Sugary fluids Approx volume (mls) = 20g
  • Lucozade 100 ml
  • Fruit juice 200 ml
  • Coke or Pepsi 200 ml
  • Lemonade 300 ml


  • 5 glucose tablets or black tea/coffee with
  • 2 tsp sugar = 10g carbohydrate

If you have diabetes you should also:

  • Test your blood sugar four hourly if it drops to 4mmol or below take a sugary drink or five glucose tablets.
  • Bring in all your medication with you.
  • The nursing staff will monitor your blood glucose.
  • After the colonoscopy you will be given food and drink. If you take diabetes medicine once a day only take half your usual dose. If you take diabetes medicine twice a day omit the am dose and only take your evening dose with your evening meal.

Essential information for patients with diabetes: Safe driving and the DVLA following your procedure

Tips on bowel preparation

  • It is a good idea to apply a barrier cream, eg. Vaseline, to your anal area, as repeated bowel actions can make you sore
  • If you find the preparation distasteful, have some juice ready to follow, or your could try drinking through a straw
  • Bowel actions usually start within half an hour of the first dose, but this can take longer.
  • It is advisable to stay close to a toilet
  • Stop drinking temporarily if you feel sick or uncomfortable; keep moving about and you should feel better
  • Bowel actions become clear after two to three hours. ALWAYS take the next dose

Other medication

  • If you are taking iron tablets, stop these five days before the examination. If you are taking any medication for constipation, please stop taking this for two to three days before the examination
  • If you are taking medication to stop your blood clotting eg. warfarin, clopidogrel, dabigatran, please contact the endoscopy office on 01935 384 793
  • It will be necessary to have your blood clotting time checked before the procedure and it may be necessary to suspend your medication until after your examination
  • If you are taking Frusemide or Bendroflumethiazide you must stop this the day you start your bowel preparation
  • Please bring a list of your medication with you. If you are having chemotherapy, please inform us on receipt of this letter

You will be advised by the endoscopist on the day as to when you can restart any medication you have stopped for this procedure.

What to bring with you

Something to read is useful as you could be with us for at least three hours. You will have a cubicle for changing and a basket will be provided for your clothes and personal belongings. This basket will remain with you throughout your stay. Please leave valuables at home. It is a good idea to bring a dressing gown and slippers as you may make several trips to the toilet. Please do not wear any type of false nails or nail varnish, as it interferes with vital signs monitoring.

What happens when I arrive

Your details will be taken and checked by our receptionist. A nurse will show you to your cubicle and ask you to put on one of our gowns. When you are ready, a nurse will take your blood pressure and ask you some questions about your health. You can then relax in your cubicle until it’s time for your procedure.


The nurse will give you a consent form when you arrive. Please read this carefully. A doctor or nurse will come and explain the procedure and answer any questions you may have. At Yeovil Hospital we do teach endoscopy trainees, who work under the supervision of a senior clinician. Please let us know if you have any questions about this.


Colonoscopy, biopsies (taking small tissue samples) and polypectomy (removal of polyps which are growths in the bowel, of which some types may become cancerous) are generally safe and complications are rare; however, they can occur and these include:

  • Bleeding from a biopsy or polypectomy site
  • A perforation or tear in the gut wall, this may require an operation to repair
  • An allergic reaction to the sedative/other medication given during the procedure

How long does it take

The duration of the procedure varies but is usually about 30 minutes, however, it can take up to an hour in some cases. We also look after emergencies and these take priority on our lists.

To reduce any discomfort you may experience during the procedure, you have a choice of two forms of pain control:

Inhaled sedation (gas and air) There are some medical conditions which may not be compatible with inhaled sedation. This will be discussed with you on the day. You will have a needle/plastic cannula placed in a vein as we may give you medication to reduce bowel spasm (not sedative). Inhaled sedation is used for the relief of pain. It is self administered through a mouthpiece which is regulated to release inhaled sedation only when you breath in. If you choose to have inhaled sedation, you will be fit to drive within 30 minutes and will not need some one to stay with you overnight. or Intravenous sedation This will be given via a needle in your hand or arm. The sedation will relax you and may make you drowsy but will not put you to sleep. You will hear what is said to you and be able to respond to any instructions given to you. The sedation will affect your judgement, memory and reflexes for up to 24 hours. As with any other medication, there is a small risk of an adverse reaction to the sedation. A nurse will attach monitors for recording your pulse. Oxygen will be administered throughout the examination if you have sedation. You will be asked to lie on your left side and a nurse will attach monitors for recording your pulse, oxygen and blood pressure. You will have to stay with us for up to two hours after the procedure. You MUST be accompanied home and have some one stay with you for the first 12 hours. The effects of the sedative can last up to 24 hours so you should not drive, operate machinery or drink alcohol during that time. We advise that you arrange alternative care for young children or elderly relatives for 24 hours after having sedation.

The procedure

The tube is inserted into your back passage, guided along the bowel. This may give you the sensation that you want to go to the toilet – relax however, as your lower bowel should be empty. The endoscopist may take a biopsy (tissue sample) of the bowel lining for investigation. If the endoscopist finds excessive tissue, such as a small polyp, that can be effectively treated at the time, they will do so unless you have indicated otherwise.


You may not feel any discomfort at all, but the following may occur:

  • A bloated feeling from air inserted during the procedure
  • You may feel you want to go to the toilet when the tube is passed and you may pass some of the air we insert, this is normal
  • You may get discomfort when the scope goes around tight bends in your colon, this is from slight stretching of the colon. If you find it too uncomfortable let us know and we can change the position or offer you more sedation.

After the procedure

The sedative may make you a little sleepy for a while. As soon as you feel ready, you will be offered a cup of tea or coffee. You will be given a report of the outcome of the procedure on the day, however, the results of any tissue samples will be available at a follow up appointment or at your GP surgery about two weeks after the examination. If a follow up appointment is necessary, it will be sent to you. You may experience some mild stomach cramps from the air which was introduced. This will soon go. You are unlikely to experience problems other than mild bloating after your colonoscopy, but if you suffer severe abdominal pain, vomiting, fever, chills or rectal bleeding of more than half a cup, contact your doctor. If any polyps are removed or any biopsies taken, you may notice a small amount of blood when you next pass a motion. You may wish to limit your activity for a day or two. You are advised not to travel by air within two weeks of your colonoscopy, particularly if you have had polyps removed.

Frequently Asked Questions:

Should I take my usual medication? Most types of medication should be taken as normal but diabetic treatment may need to be temporarily changed (see page three of this leaflet). Aspirin can be continued, but if you take any other medication to stop the blood clotting, please ask us. We can advise you when to restart any medication when you come for your test. If in any doubt, do ask. Is it better to have sedation or Entonox (gas and air) Colonoscopy should not be painful but can be uncomfortable. Either intravenous or inhaled sedation will make the procedure more comfortable. After intravenous sedation you should not drive, operate machinery for 24 hours, or drink any alcohol. You must have someone with you overnight. The effects of inhaled sedation wear off in 30 minutes. So you have a choice, and can discuss this on the day of your test. How long will the examination take? The average time for a routine colonoscopy is about 30 minutes but can take up to an hour if you are having biopsies or polyps removed. When can I go back to work? This depends whether you have had intravenous or inhaled sedation during your procedure. We advise that you refrain from work for 24 hours if you have had intravenous sedation. You must not operate machinery and your car insurance will not cover you to drive during this time. If you have had inhaled sedation (gas and air) you may return to work when you feel safe to do so. Will I be told any results after the procedure? The Endoscopist will speak to you after the procedure and explain any results to you. We will discuss the follow-up plan of care. We will give you a copy of your endoscopy report and a patient care report to explain any findings and give you advice for the next 24 hours.

Important contact numbers:

Endoscopy admissions office 01935 384793 Day Surgery Unit – between 8am and 7pm 01935 384339 After 7pm, call the Clinical Site Manager 01935 384 525

Protection your privacy and dignity

In order to preserve patients’ privacy and dignity, and to comply with Department of Health standards, the Endoscopy / Day Surgery Unit is unable to accommodate the relatives and friends of patients attending the department. Please leave a telephone number for your named contact and a member of the team will ring them when you are ready to leave the department. If they wish to wait for you in the hospital building, there are two coffee shops on Level 3 (Ground Floor) and “The Canteen” restaurant is located on Level 2. In certain circumstances, exceptions may be made if considered to be in the patient’s best interests. Please contact the Unit Sister on 01935 384 339 if you require further advice. Thank you for your cooperation.

Ref: 17-19-101 Review: 06/24