Flexible sigmoidoscopy enables the physician to look at the inside of the large
intestine from the rectum through the last part of the colon, called the sigmoid
or descending colon. Physicians may use the procedure to find the cause of
diarrhea, abdominal pain, or constipation. They also use it to look for early
signs of cancer in the descending colon and rectum. With flexible sigmoidoscopy,
the physician can see bleeding, inflammation, abnormal growths, and ulcers in
the descending colon and rectum. Flexible sigmoidoscopy is not sufficient to
detect polyps or cancer in the ascending or transverse colon (two-thirds of the
For the procedure, you will lie on your left side on the examining
table. The physician will insert a short, flexible, lighted tube into your
rectum and slowly guide it into your colon. The tube is called a sigmoidoscope.
The scope transmits an image of the inside of the rectum and colon, so the
physician can carefully examine the lining of these organs. The scope also blows
air into these organs, which inflates them and helps the physician see better.
If anything unusual is in your rectum or colon, like a polyp or inflamed
tissue, the physician can remove a piece of it using instruments inserted into
the scope. The physician will send that piece of tissue (biopsy) to the lab for
Bleeding and puncture of the colon are possible complications of
sigmoidoscopy. However, such complications are uncommon.
Flexible sigmoidoscopy takes 10 to 20 minutes. During the procedure, you
might feel pressure and slight cramping in your lower abdomen. You will feel
better afterward when the air leaves your colon.