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Sigmoidoscopy: Before Your Procedure

What is a sigmoidoscopy?

A sigmoidoscopy is a test that lets your doctor look inside the lower part of your colon. The doctor uses a lighted tube called a sigmoidoscope to look for any problems. These include small growths called polyps. They also include cancer, bleeding, and hemorrhoids.

During the test, the doctor can take samples of tissue that can be checked for cancer or other problems. This is called a biopsy. The doctor can also take out polyps.

Before the test, you will need to stop eating solid foods. You also will have an enema or take laxatives to empty your lower colon. This helps your doctor to see inside your colon during the test.

How do you prepare for the procedure?

Preparing for the procedure

  • Be sure you have someone to take you home. Anesthesia and pain medicine will make it unsafe for you to drive or get home on your own.
  • Understand exactly what procedure is planned, along with the risks, benefits, and other options.
  • If you take blood thinners or aspirin, be sure to talk to your doctor. They will tell you if you should stop taking these medicines before your procedure. Make sure that you understand exactly what your doctor wants you to do.
  • Tell your doctors ALL the medicines and natural health products you take. Some may increase the risk of bleeding or interact with the sedation medicine. Your doctor will tell you if you should stop taking any of them before the procedure and how soon to do it.
  • Make sure your doctor and the hospital have a copy of your advance care plan. If you don't have one, you may want to prepare one. It lets others know your health care wishes. It's a good thing to have before any type of surgery or procedure.
Procedures can be stressful. This information will help you understand what you can expect and it will help you safely prepare for your procedure.

Before the procedure

The preparation for these tests usually involves a thorough cleaning of the lower colon. It must be completely clear of stool (feces). Even a small amount of stool can affect the accuracy of the test.

  • You may be told to follow a liquid diet for 1 to 2 days before the test.
  • You may be told to not eat for up to 12 hours before the test.
  • You may need to have two enemas before the test.
  • You may not need special preparation, especially if you have watery or bloody diarrhea.

What happens on the day of the procedure?

  • Follow the instructions exactly about when to stop eating and drinking. If you don't, your procedure may be cancelled. If your doctor told you to take your medicines on the day of the procedure, take them with only a sip of water.

At the clinic or hospital

  • Bring a picture ID.
  • If you feel nervous about the test and want medicine to relax you, talk to your doctor or nurse. Many people don't want this kind of medicine. This is because they want to go back to their usual activities after the test.
  • You will lie on your side. The doctor will gently put a gloved finger into your anus. Then the doctor puts the scope in and moves it into your colon. It goes in easily because it is lubricated.
  • You may have cramps when air is put into the colon to help the doctor see. Try to breathe deeply and slowly through your mouth to relax your belly muscles. You may feel and hear air escape around the scope. There is no need to be embarrassed about it. The passing of air is expected.
  • The doctor may also use small tools to take tissue samples for a biopsy or to remove polyps. This does not hurt.
  • The test usually takes 20 minutes or less.

When should you call your doctor?

Call 911 anytime you think you may need emergency care. For example, call if:

  • You passed out (lost consciousness) or feel like you will faint.
  • You pass a lot of blood from your rectum.
  • You have trouble breathing.

Call your doctor, nurse call line, or seek immediate medical care if:

  • You have pain that does not get better even after passing gas.
  • You are sick to your stomach or cannot drink fluids.
  • You have new or worse belly pain.
  • You have blood in your stools.
  • You have a fever (over 38°C or 100.4°F).
  • You cannot pass stools or gas.

Watch closely for changes in your health, and contact your doctor or nurse call line (811 in Alberta) if you have any problems or questions.

Where can you learn more?

Go to

Enter M944 in the search box to learn more about "Sigmoidoscopy: Before Your Procedure".

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