During an endoscopy, a doctor inserts a thin, flexible tube with a camera and light on its tip into your body to examine your digestive tract, airways, or other internal organs. The most common type, an upper endoscopy, typically takes about 30 minutes from start to finish. You’re sedated for the procedure, so you won’t feel pain, and most people go home the same day.
Types of Endoscopy
The word “endoscopy” covers a family of procedures named for the part of the body being examined. An upper endoscopy (also called an EGD) looks at your esophagus, stomach, and the first part of your small intestine. A colonoscopy examines your large intestine. A bronchoscopy goes into your airways and lungs, while a cystoscopy looks inside your bladder. The steps below focus on upper endoscopy, since it’s the most commonly searched, but the general sequence of preparation, sedation, scope insertion, and recovery applies to most types.
How to Prepare Beforehand
Your stomach needs to be empty so the doctor has a clear view and to reduce the risk of vomiting during sedation. The standard fasting window is at least 6 hours for a light meal and 2 hours for clear liquids. If your last meal included fatty foods or meat, which slow digestion, you may be asked to fast for 8 hours or longer.
Before the procedure, your medical team will review your full health history, paying particular attention to heart conditions, breathing problems like asthma or sleep apnea, diabetes, kidney disease, and any history of seizures or strokes. These conditions can affect how you respond to sedation. If you take blood thinners, your doctor will weigh the bleeding risk of the procedure against the clotting risk of stopping your medication. Some people are asked to pause blood thinners for a few days; others continue them. This decision is made case by case, so follow whatever specific instructions your care team gives you.
What Happens During the Procedure
Once you’re in the procedure room, a nurse will place an IV line in your forearm and attach monitors to track your heart rate, blood pressure, and oxygen levels throughout.
Next comes sedation. The most common approach in the U.S. is moderate (conscious) sedation, which uses a combination of a sedative to relax you and a pain reliever delivered through your IV. You stay technically conscious and can respond to voice or touch, but you’re drowsy enough that most people remember little or nothing afterward. A newer and increasingly popular option uses a faster-acting sedative that puts you into a deeper sleep while still breathing on your own. This deeper sedation tends to wear off more quickly and makes the experience nearly painless, though it requires closer monitoring.
While the sedation takes effect, a nurse sprays a numbing anesthetic onto the back of your throat. This suppresses your gag reflex and makes it more comfortable when the scope passes through. You’ll also be given a small plastic mouth guard to bite down on, which keeps your mouth open and protects your teeth.
You’ll be positioned on your left side. The doctor then gently guides the endoscope, a tube roughly the width of your index finger, into your mouth and toward the back of your throat. You may be asked to swallow once to help the scope slide past your throat and into your esophagus. From there, the doctor advances it down into your stomach and into the upper part of your small intestine. A tiny camera on the tip sends a live video feed to a monitor, giving the doctor a detailed view of the lining of your digestive tract.
During the exam, small amounts of air or carbon dioxide are pumped through the scope to gently inflate the area being examined. This spreads the walls of your digestive tract apart so the doctor can see the tissue clearly. The entire insertion, examination, and withdrawal of the scope typically takes 15 to 30 minutes for a standard diagnostic procedure, though more complex cases can run longer.
Biopsies and Treatments During the Procedure
Endoscopy isn’t just for looking. The scope has a small channel that allows the doctor to pass tiny instruments through it to take action on what they find. If an area of tissue looks abnormal, the doctor can take a biopsy, snipping a tiny sample with forceps threaded through the scope. You won’t feel this. The sample is sent to a lab for analysis.
If the doctor finds polyps (small growths on the lining), they can remove them during the same procedure using a wire loop called a snare, which cuts and cauterizes at the same time. Smaller polyps are sometimes simply plucked off with cold forceps. For larger polyps, the doctor may first inject a small amount of saline into the base to lift the growth away from the surrounding tissue, making removal safer.
If there’s active bleeding, the doctor can treat it on the spot by injecting medication at the bleeding site, placing a small metal clip to pinch the vessel closed, or using heat to seal it. Endoscopy can also be used to stretch narrowed passages, place stents to keep a blocked area open, or remove foreign objects that have been swallowed.
Risks and Complication Rates
Endoscopy is considered very safe. Severe bleeding requiring a transfusion or additional treatment occurs in roughly 0.2% of procedures. Perforation, where the scope creates a hole in the wall of the digestive tract, is even rarer for standard diagnostic exams. Risk increases somewhat with therapeutic procedures like polyp removal or tissue dissection, and studies show that higher-volume centers tend to have lower complication rates than facilities that perform fewer procedures.
The most common sedation side effects are mild: temporary low blood pressure, brief dips in oxygen levels, or nausea. Serious reactions to sedation are uncommon, especially with the continuous monitoring that’s standard during every procedure.
Recovery and Getting Home
After the scope is withdrawn, you’re moved to a recovery area where nurses monitor you as the sedation wears off. Most people are alert enough to be discharged within about 50 minutes, though the observation period may last up to 2 hours depending on your vitals, the type of procedure, and how quickly you bounce back. For more involved procedures like removing a large area of tissue or placing a stent, observation can extend to 4 to 6 hours.
Recovery nurses will check that you can answer questions clearly and walk steadily before letting you go. You’ll need someone to drive you home. Current guidelines recommend avoiding driving, operating heavy machinery, and making important legal or financial decisions for 24 hours after sedation. Some research suggests that psychomotor function returns to normal within 1 to 2 hours when faster-acting sedatives are used, but the 24-hour restriction remains the standard recommendation.
In the hours after the procedure, it’s normal to have a mild sore throat from the scope, and you may feel bloated or gassy from the air that was pumped in during the exam. These symptoms typically resolve on their own within a day. Most people can start with sips of water and light foods shortly after waking up and return to a normal diet by the next day. One study of colonoscopy patients found that the median time to feel completely back to normal was about 20 hours after the procedure, so plan on taking it easy for the rest of the day.
Biopsy results usually come back within a few days to two weeks. Your doctor’s office will contact you with the findings and let you know if any follow-up is needed.