Endoscopy (EN-dos-skopy) also referred to as gastrointestinal endoscopy involves the examination of inside of the Gullet and Colon. This examination is undertaken using a special fibre-optic flexible tube with a camera at its tip/ end.  The images are projected onto a monitor so that your surgeon can clearly see the inside lining of your bowel or gullet.
Endoscopy can be performed in the large majority of cases as a day case procedure under sedation. A general anaesthetic is rarely required but sometimes is necessary.
Depending upon the part of the digestive tract (mouth to anus) examined by the endoscope it is named accordingly:

Gastroscopy - Oesophagus (food pipe), stomach and duodenum (first part of small bowel)
  
Flexible sigmoidoscopy - Rectum and sigmoid colon (lower 50 cm of the bowel)

Colonoscopy - Entire colon/ large bowel

For all procedures if you are taking any medication especially blood-thinning drugs, as listed below, please ensure that your Surgeon is aware beforehand:

Aspirin
Warfarin
Clopidogrel (plavix)
Iron Tablets

If you are a Diabetic please make sure you inform your surgeon.