What Is It?

Sigmoidoscopy is an examination of the bottom one-third of your large intestine, including your rectum and the bottom part of your colon. To perform this exam, your doctor uses a sigmoidoscope — a flexible viewing tube with a light and a lens or video camera on one end, and an eyepiece or video monitor on the other. The sigmoidoscope allows your doctor to view the inside of your bowel through bundles of flexible glass fibers (fiber-optic technology).

During sigmoidoscopy, your doctor can check your rectum and part of your colon for cancer, ulcers and abnormal growths called polyps. The procedure usually takes less than 15 minutes, and can be done in your doctor’s office. There is usually very little discomfort, since the sigmoidoscope is lubricated and bends easily.

What It’s Used For

Sigmoidoscopy is used to diagnose certain bowel problems such as unexplained bleeding, diarrhea, constipation or rectal pain. If your doctor sees a suspicious area during sigmoidoscopy, he can use an attachment at the end of the sigmoidoscope to take a piece of tissue to be sent to the laboratory and examined under a microscope (biopsy). If an abnormality is found during a sigmoidoscopy, a full colonoscopy may be recommended

Sigmoidoscopy also is used to screen for colorectal cancer. It usually is done once every five years, beginning at age 50. Sigmoidoscopy may be combined with fecal occult blood testing or a barium enema to ensure that cancer is not missed in the upper part of the colon. Alternatively, your doctor may recommend a full colonoscopy every five to 10 years.


The last part of your large intestine needs to be fairly empty during sigmoidoscopy to give your doctor a clear view of your intestinal wall. To help empty your bowel, your doctor will give you specific directions about using enemas the day of the procedure. In some cases, you may be asked also to use laxatives the day before the procedure. This preparation is typically more limited than for colonoscopy. On the day of your appointment, you may be asked to not eat or to limit yourself to mostly liquids. Your doctor will give you more exact details about diet when you schedule your sigmoidoscopy exam.

Your doctor also may ask you to stop taking certain medications for up to a week before the procedure, including aspirin, warfarin (Coumadin) and iron supplements.

How It’s Done

Before getting started, the procedure will be explained to you, and you will be asked to sign a consent form. You also may be asked to provide some basic information about your medical history, the medications you take and your allergies.

Then you will put on a hospital gown, and your doctor’s assistant will record your temperature, pulse, blood pressure and respiratory rate (number of breaths per minute). You will be asked to lie on your side on an examination table, with one or both of you knees raised to your chest. The lower portion of your body will be covered with a sheet. The doctor will insert a lubricated, flexible sigmoidoscope into your rectum and, as necessary, pump a small amount of air through the sigmoidoscope to open up your intestinal passage for a clearer view. Your doctor also may take a stool sample or piece of tissue for a biopsy from inside your bowel.

Although people often worry that they will be uncomfortable during a sigmoidoscopy, you should not experience anything worse than a sense of pressure or mild cramping. Pain medications or sedatives rarely are needed, and the procedure often takes as few as five minutes to complete. Tell your doctor immediately if you develop severe pain or other type of discomfort during the sigmoidoscopy.


After sigmoidoscopy is done, you can get dressed and return to your normal diet and daily schedule. If your doctor took a stool sample or a piece of tissue for a biopsy during the exam, check back in a few days for the results.


Although it is possible that your bowel might be injured during sigmoidoscopy, this complication is rare, occurring in about one in 10,000 procedures.

When To Call A Professional

Call your doctor immediately if you see any bleeding from your rectum after sigmoidoscopy or if you feel faint, dizzy, short of breath or have palpitations. Also call your doctor if you have nausea, vomiting, cramps or any other type of abdominal pain, or if you develop a fever, chills, severe headache or muscle aches.

Johns Hopkins patient information

Last revised:

Diseases and Conditions Center

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.