Endoscopy and Colonoscopy: What to Expect

What These Procedures Are

Both use a thin, flexible tube with a camera. In an upper GI endoscopy (gastroscopy), it is passed through the mouth to examine the food pipe, stomach and the start of the small intestine. In a colonoscopy, it is passed through the back passage to examine the entire large intestine. The doctor sees a clear, magnified view on a screen and can take small tissue samples (biopsies) or remove growths like polyps during the same procedure.

Why They Are Done

Endoscopy investigates symptoms such as persistent heartburn, difficulty swallowing, stomach pain, or unexplained anaemia. Colonoscopy investigates changes in bowel habit, bleeding, or abdominal symptoms — and importantly, screens for and prevents colorectal cancer by finding and removing polyps before they turn cancerous. These are among the most useful diagnostic tools in medicine.

Preparation Matters

For endoscopy, you fast for several hours so the stomach is empty. For colonoscopy, preparation is more involved: a special cleansing regimen the day before empties the bowel completely, because the view is only as good as the preparation. Following the prep instructions carefully is the single most important thing a patient can do to ensure an accurate colonoscopy.

During and After

Both are usually done with sedation, so most people are comfortable and remember little. The procedures themselves typically take fifteen to forty-five minutes. Afterwards, you rest until the sedation wears off, and because of the sedation you will need someone to accompany you home. Most people resume normal eating and activity the next day.

Common Questions