When Do You Need an Endoscopy? Reasons, Preparation and What to Expect

Medically reviewed by Dr Usman Naeem, 24 Oct 2026.

What is an endoscopy?

A thin, flexible tube with a light and camera is passed gently through the mouth. The doctor can see the lining, take small painless tissue samples (biopsies) and, when needed, treat problems such as a bleeding ulcer or varices during the same test. The examination itself usually takes around 5 to 15 minutes, although you will be at the hospital for longer.

A colonoscopy is a different test that looks at the large bowel through the back passage. It is covered in our article on blood in stool.

When is it advised?

Your doctor may suggest an endoscopy if you have:

• Vomiting blood or black stools (this is usually done urgently in hospital)
• Difficulty or pain when swallowing, or food sticking
• Indigestion with warning signs such as weight loss, anaemia or persistent vomiting, or new symptoms at an older age
• Acidity or upper stomach pain that continues despite treatment
• Suspected coeliac disease, when duodenal biopsies are needed
• Cirrhosis, to check for varices (swollen veins) that may need treatment
• Follow-up of conditions such as a stomach ulcer or Barrett’s oesophagus

How to prepare

• Fasting: usually nothing to eat for about 6 hours before. Small sips of clear water may be allowed until around 2 hours before. Always follow the exact instructions you are given
• Medicines: tell the team in advance if you take blood thinners (such as warfarin, clopidogrel, rivaroxaban or apixaban), insulin or diabetes tablets. Do not stop them on your own; the doctor will advise
• Bring a list of your medicines, previous reports and any allergy information
• If you will have sedation, come with a family member or friend who can take you home

On the day

The doctor will explain the test and ask for your consent, and you can ask any questions. A numbing spray may be used on the throat, and many people are given sedation through a small cannula so they feel relaxed and drowsy. A mouth guard protects your teeth. You lie on your left side and breathe normally through your nose and mouth; the tube does not block your breathing.

Some bloating or a mild sore throat afterwards is common and settles quickly. The doctor will usually explain what was seen before you leave. Biopsy results take longer and are discussed at follow-up.

After sedation

• Do not drive, ride a motorbike, operate machinery or sign important documents for the rest of the day
• Have someone stay with you for a few hours if possible
• You can usually eat and drink once the throat numbness wears off, unless told otherwise

Is it safe?

Diagnostic upper endoscopy is a very safe test. Serious complications are rare. They include a reaction to sedation, bleeding (more likely after biopsies or treatment) and, very rarely, a tear (perforation). The risk is somewhat higher when treatment is carried out, and the doctor will discuss your own risks before the test.

Common questions

Related condition guides

More articles

• High SGPT (ALT) in Your Blood Test: What It Means and What to Do Next
• Fatty Liver Diet: A Practical Guide with Everyday Pakistani Food
• Blood in Stool: Common Causes, When to Worry and When a Colonoscopy Is Needed
• Hepatitis B and C in Pakistan: Which Tests You Need and How Treatment Works
• Acidity and H. pylori: Symptoms, Testing and When to See a Doctor
• Cirrhosis Diet: What to Eat and What to Avoid
• Water in the Belly (Ascites): Causes, Tests and Care
• Yellow Eyes (Jaundice): Causes, Tests and When to Worry

General information only, not personal medical advice. Do not start or stop medicines because of this article. See the medical disclaimer.