Bowel Transit Time

Test Overview

A bowel transit time test measures how long it takes for food to travel through the digestive tract. Bowel transit time depends on what types of food you eat and how much you drink. For example, people who eat lots of fruits, vegetables, and whole grains tend to have shorter transit times than people who eat mostly sugars and starches. Because different people have different transit times, experts disagree about how useful this test is.

After you chew and swallow your food, it moves into your stomach, where it is mixed with acid and digestive enzymes. After your food leaves your stomach, it is squeezed through your small intestine, where, vitamins and water are absorbed for use by your body. The food then goes into your large intestine (colon). Whatever hasn't been digested and absorbed by your intestines combines with water, bacteria, and other waste products and becomes stool (feces). Stool is expelled from your body through your anus. The time it takes for food to travel from your mouth to your anus as stool is your bowel transit time.

There are several methods to test your bowel transit time. Each method uses a swallowed substance (called a food marker) that goes through your body and leaves in your stool without being digested. Because the results of these tests are not consistent, experts disagree about their usefulness. Some doctors do not recommend bowel transit time testing.

Dye test

For a dye test, you swallow a pill that has dye in it and keep track of how long it takes before the dye shows up in your stool.

Home test

For a home test, you will drink some red vegetable dye or eat a food like corn kernels or beets. You will then keep track of how long it takes for the dye or vegetable to show up in your stool.

Pellet test

For a pellet test, you swallow small pills (pellets) before having X-rays of your belly. The pellets look like white spots or rings in the X-ray pictures. You will have X-rays over 2 or 3 days to keep track of how fast the pellets move through your intestines.

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Author:	Sydney Youngerman-Cole, RN, BSN, RNC	Last Updated: May 5, 2006
Medical Review:	Kathleen Romito, MD - Family Medicine Peter J. Kahrilas, MD - Gastroenterology Jerome B. Simon, MD, FRCPC, FACP - Gastroenterology
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