Bowel transit time

• How the test is performed

  You will be asked to swallow two gelatin capsules filled with carmine red or another food dye. You take the special capsules with a meal.

  Afterwards, you observe your bowel movements and write down how long it takes for the colored dye to first appear. You'll also need to note how long it takes for the color to disappear from the stools.

• How to prepare for the test

  No preparation is usually needed. However, you should follow any diet or other directions from the health care provider.

• How the test will feel

  You will not feel the capsules move through your gastrointestinal system.

• Why the test is performed

  The test helps determine bowel function.

  Your doctor may ask you to record transit times you introduce fiber into your diet. Your diet affects the bowel transit time. For example, if you eat a lot of foods rich in fiber (whole grains, vegetables, and fruits), you have a more rapid transit time and a heavier, bulkier stool.

• Normal Values

  The bowel transit time varies even in the same person. The first of the color should appear in the stool about 12 - 14 hours after it is taken. The last of the color will appear within 36 - 48 hours.

• What abnormal results mean

  If the times are much longer, 72 hours or more, it may indicate a slowed bowel function. A high fiber diet should speed the bowel transit time up.

• What the risks are

  There are no risks.

• Special considerations

  The bowel transit time dye test is rarely performed these days.

Review Date: 8/22/2008

Reviewed By: Christian Stone, MD, Division of Gastroenterology, Washington University in St. Louis School of Medicine, St. Louis, MO. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.