Your doctor has scheduled a defecography for you. This handout will tell you how to prepare and what will happen during the exam.

If you have questions, please call Radiology at (608) 263-9729, press #2.

Let us know if:

  • There is any chance you may be pregnant.

  • You have had rectal surgery in the past.

  • You have a history of chronic colitis.

  • You have any renal (kidney) disease.

  • You have heart problems.

  • You have diabetes.

If you have any of these, you may need more instructions.

If you have other tests scheduled before this exam, ask your doctor if you need to change your pre-exam schedule.

If you are taking medicines, ask the doctor about taking them in the 24 hours before the exam.


A defecography is an x-ray of the rectum and sigmoid (lower) portion of the colon while you are emptying contrast from your bowel. In order to see parts of the rectum, it will be filled with contrast. If present, the vagina will also be filled with a small amount of contrast. Prior to the examination, you will drink contrast, so your small bowel is visible as well.

Day of the Exam

Prior to arriving to the Radiology Department, please give yourself a rectal cleansing enema. You can purchase this without a prescription from any drugstore.

If you are an inpatient, you will be taken to Radiology.

If you are an outpatient, go to the place where the exam is scheduled. It will either be Digestive Health Center Radiology or UW Hospital Radiology (G3/3Atrium elevators to the 3rd floor). Arrive at the time scheduled.

When you arrive, we will ask you to drink two cups of contrast before the exam. This will help show your small bowel.

We will give you a robe and gown to put on.

The Procedure

If you have a vagina, we will place a lubricated tube in it and fill it with contrast gel.

We will place a lubricated tube into your rectum. We will use contrast paste to fill the rectum. Using a special screen, the radiologist will watch your rectum empty while you sit on a commode. The lights will be dim so the doctor can see the screen clearly. You will hear the x-ray machine make a humming noise.

We will take pictures and video images during the exam and elimination process. This part of the exam takes only a few minutes. You may then expel any remaining contrast in a nearby bathroom.

After the Exam

The radiologist will communicate the results of the exam to your doctor. Your doctor will then talk with you and suggest further treatment, if needed.

Ask the doctor if you should take two tablespoons of milk of magnesia to help you expel any extra contrast in your bowel.

Your bowel movements may be whitish in color for a day or two. This is normal. This color is caused by traces of contrast still in your bowel. Drink plenty of fluids to help wash the contrast out.

You may continue your usual diet unless your doctor tells you otherwise.