To prepare for an upper endoscopy, you’ll usually stop eating solid food 6 to 8 hours beforehand and stop clear liquids about 2 hours before. Arrange for someone to drive you home if you’re having sedation, and check with your doctor in advance about any blood thinners, diabetes medications, GLP-1 injections and acid-reducing drugs. The procedure itself usually takes only 10 to 20 minutes. Between check-in, sedation and recovery, plan for about two to three hours at the unit.

Most people are far more anxious about an endoscopy than the procedure deserves. With sedation, most people remember very little. Without it, the worst part is usually a few seconds of gagging as the scope goes past the back of the throat. The preparation is what you need to get right. If you eat too late, the procedure gets cancelled. If you take the wrong medication, the results can be misleading.

If you’ve been sent for an endoscopy because of reflux, it also helps to know what the camera can and can’t see. I’ve worked with a lot of people who were told their scope was “normal” and assumed that meant their reflux wasn’t real. That isn’t what a normal result means, and I’ll explain why below.

Key Takeaways

An upper endoscopy (also called a gastroscopy or EGD) uses a thin, flexible camera to look at your esophagus, stomach and the first part of your small intestine.
Standard fasting guidance allows clear liquids up to 2 hours before sedation and a light meal up to 6 hours before. Fatty or fried food may need 8 hours or more. Always follow your own unit’s instructions if they’re stricter.
Tell your team in advance about blood thinners, diabetes medications and GLP-1 drugs like Ozempic or Mounjaro, because these often need adjusting.
If the endoscopy is meant to confirm GERD, your doctor may ask you to stop your PPI for 2 to 4 weeks beforehand. Don’t stop it unless you’ve been told to.
The procedure itself typically takes 10 to 20 minutes. With sedation, you’ll need someone to drive you home, and you shouldn’t drive for the rest of the day.
Serious complications are rare. A sore throat and some bloating afterward are the most common side effects.
A normal endoscopy does not rule out reflux. Many people with real reflux, especially silent reflux (LPR), have an esophagus that looks completely normal.
Biopsy results usually take one to two weeks, so the conversation you have on the day may only be part of the picture.

What an Upper Endoscopy Actually Is

An upper endoscopy is a camera examination of your upper digestive tract. A thin, flexible tube with a light and camera on the end is passed through your mouth, down your esophagus, into your stomach and just into the duodenum (the first part of the small intestine). The doctor watches the image on a screen, takes photos, and can take tiny tissue samples (biopsies) through a channel in the scope.

For reflux, the main things the doctor is looking for are:

Esophagitis: inflammation or erosions in the lower esophagus caused by acid. See erosive esophagitis.
Barrett’s esophagus: a change in the lining of the lower esophagus that needs monitoring. See Barrett’s esophagus symptoms.
A hiatal hernia: part of the stomach pushing up through the diaphragm. See hiatal hernia and reflux.
Strictures or narrowing, which can sometimes be stretched during the same procedure. See esophageal dilation.
Gastritis, ulcers and H. pylori, which are checked with stomach biopsies. See gastritis vs acid reflux.
Eosinophilic esophagitis, an allergic condition that mimics reflux and can only be confirmed with biopsies. See eosinophilic esophagitis vs acid reflux.

For the general reasons doctors order one in the first place, see my guide to endoscopy for acid reflux. This article is about the practical side: getting ready, the day itself, and what happens afterward.

How to Prepare for an Endoscopy

Fasting: when to stop eating and drinking

Your stomach needs to be empty, for two reasons. The doctor can’t see the lining through food, and an empty stomach lowers the risk of inhaling stomach contents while you’re sedated.

The American Society of Anesthesiologists’ fasting guidance, which applies to procedural sedation as well as general anesthesia, allows clear liquids up to 2 hours before. A light meal or non-human milk is allowed up to 6 hours before. Fried or fatty foods and meat may need 8 hours or more [American Society of Anesthesiologists, Anesthesiology, 2017]. A 2023 update covered carbohydrate drinks and chewing gum but didn’t change the core timings [Joshi et al., Anesthesiology, 2023].

In practice, many units simplify this to “nothing to eat after midnight” for a morning appointment, or “nothing to eat for 6 hours” for an afternoon one. If your unit gives you stricter instructions, follow theirs.

Clear liquids means liquids you can see through:

Water
Clear apple juice (no pulp)
Black tea or black coffee (no milk or creamer)
Clear broth
Plain gelatin

Milk, smoothies, orange juice with pulp and alcohol are not clear liquids.

A reflux tip: keep your last meal light and low in fat. Fat slows stomach emptying, and a big rich dinner the night before is the classic way to arrive with food still in your stomach. Something like plain chicken with rice or potato is ideal. If you need ideas, my list of LPR-friendly foods works well here.

Medications to discuss with your doctor first

Raise these when the endoscopy is booked, not on the morning:

Blood thinners (warfarin, apixaban, rivaroxaban, clopidogrel and similar). These may need to be paused or adjusted if biopsies or dilation are likely. Never stop one on your own.
Diabetes medications, including insulin. Fasting changes your dosing needs, so you’ll usually get specific instructions.
GLP-1 drugs (Ozempic, Wegovy, Mounjaro, Zepbound). These slow stomach emptying, so food can still be in the stomach well beyond the usual fasting window. Units often give specific instructions for these. See Ozempic and reflux.
Iron tablets can stain the lining dark. Some units ask you to stop them a few days before.
Blood pressure, heart, thyroid and seizure medications are usually taken as normal with a small sip of water, but confirm this with your unit.

Should you stop your PPI before an endoscopy?

Ask your doctor this question directly, because the answer depends on why you’re being scoped.

If the aim is to confirm whether you have GERD at all, being on a PPI can heal mild esophagitis and hide the evidence. For patients whose diagnosis hasn’t been proven, the American College of Gastroenterology suggests performing the endoscopy after the PPI has been stopped for 2 to 4 weeks [Katz et al., American Journal of Gastroenterology, 2022].

If the aim is to check healing, look for Barrett’s esophagus, or investigate swallowing problems, you’ll often stay on your PPI.

If you’re told to stop, don’t stop abruptly if you’ve been on it for months. Rebound acid can make those weeks miserable. My guide to getting off PPIs and managing acid rebound covers how to taper and what helps in the meantime. An alginate such as Gaviscon Advance after meals and at bedtime can help, but ask whether your unit wants you to stop alginates and antacids the day before too.

What to bring and wear

A list of your medications and doses.
Loose, comfortable clothing.
No jewelry, plus a case for glasses, contact lenses or dentures, which may need to come out.
Your symptom history, written down. Note what your symptoms are, when they started, what makes them worse and what you’ve tried. Throat symptoms like hoarseness, throat clearing or a lump sensation are worth mentioning specifically, because they point toward LPR rather than classic GERD.
The name and phone number of the person collecting you.

Sedated or Unsedated?

Most upper endoscopies in the US are done under sedation, ranging from light “twilight” sedation to deeper propofol sedation given by an anesthesia provider. In the UK and parts of Europe, many people choose a numbing throat spray with no sedation, or with light sedation only.

With sedation, you’ll be relaxed or asleep and will probably remember little. The trade-off is that you need someone to take you home, and you can’t drive, work or sign anything important for the rest of the day.

Without sedation, you’ll be aware throughout and may gag for a few seconds as the scope passes, but you can leave almost immediately. Some centers also offer transnasal endoscopy, which uses an ultra-thin scope passed through the nose. It’s usually done without sedation and tends to trigger less gagging. In one study, unsedated transnasal endoscopy detected Barrett’s tissue in 31 of 32 known patients, and its biopsy results agreed well with those from standard sedated endoscopy [Saeian et al., Gastrointestinal Endoscopy, 2002]. It isn’t available everywhere, but it’s worth asking about if you’re nervous about sedation or can’t arrange a lift home.

What Happens on the Day

Check-in and assessment. A nurse confirms your fasting, medications and allergies, checks your blood pressure and oxygen levels, and goes through the consent form. This is a good time to repeat your main symptoms.
Cannula and sedation. If you’re having sedation, a small cannula goes into a vein in your hand or arm. You may get a throat spray, which tastes bitter and makes your throat feel thick.
Positioning. You lie on your left side, and a plastic mouthguard protects your teeth and the scope.
The procedure. The scope is passed down while air or carbon dioxide gently inflates the area so the doctor can see. This usually takes 10 to 20 minutes, a little longer if biopsies or dilation are needed. Biopsies are painless.
Recovery. You rest while the sedation wears off, usually for 30 to 60 minutes. You may feel bloated and burp a lot from the air.
Initial results. The doctor or nurse usually tells you what was seen before you leave. Write it down or have your companion listen, because sedation affects memory.

After the Endoscopy

Sore throat: common for a day or two. Cool water and soft, non-acidic food help.
Bloating and burping: from the air used during the procedure. This settles within hours.
Eating: once the throat numbness has worn off, usually within an hour, start with something light. If you had dilation, you may be told to stick to soft foods for the rest of the day.
Driving and decisions: after sedation, don’t drive, operate machinery, drink alcohol or make important decisions until the next day.

Serious complications from a diagnostic upper endoscopy are uncommon. The American Society for Gastrointestinal Endoscopy lists bleeding (mostly after biopsies or therapeutic procedures), perforation, reactions to sedation and infection as rare risks. The risk rises when procedures like dilation are performed [ASGE Standards of Practice Committee, Gastrointestinal Endoscopy, 2012].

Seek urgent help if you develop severe or worsening chest, neck or abdominal pain, a fever, difficulty breathing, vomiting blood, or black, tarry stools after an endoscopy.

What an Endoscopy Can and Can’t Tell You About Reflux

This is the part most people aren’t told, and it’s the reason so many leave the endoscopy unit confused.

A normal endoscopy doesn’t rule out reflux

Most people with reflux symptoms don’t have visible damage. In a Swedish study where 1,000 randomly selected adults had an endoscopy, 40% reported reflux symptoms, but only 15.5% had esophagitis [Ronkainen et al., Gastroenterology, 2005]. The international Lyon Consensus on GERD diagnosis states plainly that “a normal endoscopy does not exclude GERD” [Gyawali et al., Gut, 2018].

If your endoscopy is normal but your symptoms are still there, the next step is often a pH-impedance test, which measures reflux events directly over 24 hours.

It barely looks at the throat

An upper endoscopy is designed to examine the esophagus and stomach. The scope passes the throat quickly on the way down, but it isn’t a detailed throat examination. If your main symptoms are throat-based (hoarseness, constant throat clearing, a lump sensation, post-nasal drip or a chronic cough), the more relevant exam is often a laryngoscopy by an ENT.

This is the typical silent reflux (LPR) pattern. The esophagus often looks fine, because the damage in LPR is driven by pepsin reaching throat tissue, which is far more sensitive than the esophagus. See GERD vs LPR and ENT or gastroenterologist for LPR.

Questions to ask before you leave

Was there any esophagitis, and if so, what grade (LA grade A to D)?
Did you see a hiatal hernia, and how large was it?
Were biopsies taken, and what are they testing for (H. pylori, Barrett’s, eosinophilic esophagitis)?
When and how will I get the biopsy results?
Was I on a PPI during this test, and does that affect what you could see?
If everything looks normal, what’s the next test for my symptoms?

Conclusion

Preparing for an endoscopy comes down to a few basics: an empty stomach (about 6 to 8 hours for food, 2 hours for clear liquids), a medication plan agreed in advance, a lift home if you’re sedated, and a clear answer on whether to stop your PPI. The procedure itself is short, and most people find it far easier than they feared.

Go in knowing its limits, though. An endoscopy is good at finding damage in the esophagus and stomach, but most people with reflux, and nearly everyone with silent reflux, have no visible damage. A normal result means “no visible damage today”, not “no reflux”.

Whatever your results show, what you eat day to day will decide how much reflux reaches your esophagus and throat. If you want a structured plan to follow while you wait for results or answers, the Wipeout Diet Plan gives you a step-by-step approach. I built it around LPR, the hardest form of reflux to control, and it works just as well for GERD and everyday heartburn.

Frequently Asked Questions

How long does an endoscopy take?

The procedure itself usually takes 10 to 20 minutes, or a little longer if biopsies or dilation are needed. With check-in, sedation and recovery, expect to be at the unit for about two to three hours.

Can I drink water before an endoscopy?

Usually yes, up to about 2 hours before the procedure. Standard fasting guidance allows clear liquids until then, but always follow your own unit’s instructions, which may be stricter.

Is an endoscopy painful?

Generally no. With sedation, most people remember very little. Without sedation, the main discomfort is gagging as the scope passes the back of the throat, plus some bloating. Biopsies don’t hurt.

Should I stop taking omeprazole before an endoscopy?

Only if your doctor tells you to. If the endoscopy is meant to confirm GERD, you may be asked to stop for 2 to 4 weeks so the PPI doesn’t hide inflammation. If it’s to check healing or Barrett’s esophagus, you’ll often stay on it.

Can I brush my teeth before an endoscopy?

Yes. Brushing your teeth is fine as long as you don’t swallow the water or toothpaste.

How long after an endoscopy can I eat?

Usually once the throat numbness wears off, typically within about an hour. Start with something light. If you had a dilation, you may be told to stick to soft foods for the rest of the day.

Can an endoscopy diagnose silent reflux?

Not on its own. Most people with silent reflux have a normal-looking esophagus. LPR is usually diagnosed from your symptoms, a throat exam (laryngoscopy) and sometimes pH-impedance testing.

Research & References

American Society of Anesthesiologists guidance allowing clear liquids up to 2 hours and a light meal up to 6 hours before procedures with sedation or anesthesia, with 8 or more hours suggested after fried or fatty food or meat [American Society of Anesthesiologists, Anesthesiology, 2017].
A modular update of the 2017 fasting guidelines covering carbohydrate-containing clear liquids, chewing gum and pediatric fasting duration [Joshi et al., Anesthesiology, 2023].
The American College of Gastroenterology’s clinical guideline on the diagnosis and management of GERD, including when to perform endoscopy and the role of PPI withdrawal before testing [Katz et al., American Journal of Gastroenterology, 2022].
An international consensus on GERD diagnosis stating that a normal endoscopy does not exclude GERD and setting out which test findings give conclusive evidence of reflux [Gyawali et al., Gut, 2018].
A population study of 1,000 Swedish adults who had an endoscopy: 40% reported reflux symptoms, but only 15.5% had esophagitis [Ronkainen et al., Gastroenterology, 2005].
A study showing that unsedated transnasal endoscopy detected Barrett’s metaplasia in 31 of 32 known patients, with dysplasia findings agreeing well with conventional endoscopy [Saeian et al., Gastrointestinal Endoscopy, 2002].
An American Society for Gastrointestinal Endoscopy review of adverse events after upper GI endoscopy, including bleeding, perforation, sedation-related events and infection [ASGE Standards of Practice Committee, Gastrointestinal Endoscopy, 2012].

David Gray

12 years living with LPR · Consultant & researcher

Every claim sourced to peer-reviewed research Editorial policy

I've lived with LPR for twelve years — the misdiagnoses, the PPI courses that did nothing, the slow work of figuring out what actually helps. Wipeout Reflux is where I translate the research into plain terms for people stuck in the same place. Every claim here is sourced to peer-reviewed work, and I consult one-to-one with LPR sufferers.

View all articles by David Gray

How to Prepare for an Endoscopy (and What to Expect)