by EBSCO Medical Review Board


Esophageal pH monitoring measures how much acid is in the tube that joins the mouth to the stomach. A small pod is placed in the tube. It will send data to a receiver device worn on the waist.

Reasons for Procedure

pH is monitored to test how much acid is moving up from the stomach. It can also show how long the acid stays there. This will help to plan or track treatment for gastroesophageal reflux disease (GERD).

Possible Complications

Problems are rare, but all procedures have some risk. The doctor will go over some problems that may happen, such as:

  • The pod becomes loose
  • Sore throat
  • Problems from anesthesia
  • Infection
  • Bleeding
  • Chest pain
  • Problems swallowing when food passes by the capsule
  • Harm to the esophagus

Things that may raise the risk of problems are:

  • Long-term diseases such as diabetes
  • Bleeding problems
  • Certain medicines

What to Expect

Prior to Procedure

The care team may meet with you to talk about:

  • Any allergies you may have
  • Whether you need a ride to and from the test
  • Current medicines, herbs, and supplements that you take and whether you need to stop taking them before the test
  • Fasting before the test, such as avoiding food or drink after midnight the night before


You may have:

  • Moderate sedation—you will be sleepy and may not feel pain
  • Local anesthesia—your throat will be numbed

Description of the Procedure

A long tube with a light and camera will be put in the mouth. You will be asked to try to swallow it. The camera will show where the tube is. Once it is in the right place, the pod will be connected to tissue. The tube will be removed.

The pod will fall off in about a week. It will pass through the body in stool (poop).

How Long Will It Take?

30 minutes

Will It Hurt?

There is some discomfort during the test. A sore throat is common for 1 to 2 days after the test. Pain medicine can help if needed.

Post-procedure Care

At the Care Center

The staff will give you a receiver that collects the data. They will tell you how to wear it and for how long.

At Home

The monitor will need to be worn for about 48 hours.

Problems to Look Out For

Call your doctor if you have:

  • Signs of infection, such as fever and chills
  • Problems swallowing or breathing
  • Nausea and vomiting
  • Cough
  • Chest pain
  • Bleeding
  • Problems using the receiver

If you think you have an emergency, call for medical help right away.


American Gastroenterological Association 

American Society for Gastrointestinal Endoscopy 


Canadian Digestive Health Foundation 

Health Canada 


Ambulatory pH monitoring. Merck Manual Professional Version website. Available at: Accessed May 17, 2022.

Esophagus: 48-hour Bravo esophageal pH test: Test details. Cleveland Clinic website. Available at: Accessed May 17, 2022.

Gastroesophageal reflux disease (GERD). EBSCO DynaMed website. Available at: Accessed May 17, 2022.

National Institute for Health and Clinical Excellence (NICE). Dyspepsia and gastro-esophageal reflux disease: Investigation and management of dyspepsia, symptoms suggestive of gastro-esophageal reflux disease, or both. NICE 2014 Sep:CG184.

Richter JE, Rubenstein JH. Presentation and epidemiology of gastroesophageal reflux disease. Gastroenterology. 2018;154(2):267-276.

Revision Information