An endoscopy is a surgical procedure whereby a long, thin, flexible tube called an endoscope is inserted into your body in order to investigate unusual symptoms or carry out certain types of surgery. Find out about different endoscopies used in gastroenterology in our short Patients Guide.

What is an endoscope?

The endoscope has a light source and a camera at one end which relays images from inside your body onto a television screen. This allows the doctor to see what is going on inside you. Endoscopes can also be used to remove small samples of tissue for analysis in a procedure known as a biopsy.

Different types of endoscopy

There are several different types of endoscopy depending what you are being examined for:

  • A colonoscopy examines the large intestine.
  • A sigmoidoscopy examines the rectum and lower part of the bowel.
  • A laparoscopy is type of keyhole surgery carried out via a small cut in your skin.
  • A virtual colonoscopy (or CT colonoscopy) examines the lining of the large bowel using a CT scanner to X-ray the bowel.
  • An upper tract endoscopy examines the lining of the upper gastrointestinal tract to diagnose conditions affecting the oesophagus, stomach and upper intestines.

What happens during an endoscopy?

When you have an endoscopy, the tube is either inserted through a natural opening – your mouth, bottom or urethra (the tube you wee through) – or via a small incision in the skin if you are undergoing keyhole surgery.

Depending which part of your body is being examined you may be asked not to eat or drink before the procedure. If you are having a colonoscopy you may be given laxatives to empty your bowels. If you are taking medication such as warfarin or clopidogrel which thin the blood you may be asked to stop taking it a few days before the endoscopy to minimise the risk of bleeding. In some cases you may be given antibiotics to reduce the risk of developing an infection.

You will normally be conscious during an endoscopy. You may be offered a sedative to help you to relax and you may have a local anaesthetic to numb part of your body before the procedure takes place. Once the anaesthetic has taken effect, the endoscope will be gently inserted into your body.

The procedure will normally take between 15 and 60 minutes. It will be done as an outpatient which means you won’t have to stay in hospital overnight.


Will it hurt?

Endoscopies are not normally painful. Most people only experience mild discomfort, akin to indigestion or a sore throat. The anaesthetic or sedative should help with this.

What are the side effects?

The risk of serious complications associated with endoscopy are very low. Possible complications include an infection in the part of the body that is examined. If this is the case you will be given antibiotics to treat the infection. Another possible complication is piercing or tearing of an organ or excessive bleeding. On the rare occasions that this occurs, you may need surgery to repair the tissue or organ damage and possibly a blood transfusion.

Mild side effects include a reaction to the sedative, which can range from sickness to irregular heartbeat or breathing difficulties.

Patients who undergo an endoscopy are advised to contact their GP if the notice any of the following:

  • signs of infection (redness, pain or swelling; discharge of fluid or pus; high temperature)
  • black or dark-coloured poo
  • shortness of breath
  • severe or persistent abdominal pain
  • chest pain
  • vomiting blood

Working with a specialist will ensure you have expert care through your endoscopy procedure and accurate diagnosis of any findings.