Flexible sigmoidoscopy is a targeted lower-colon exam that helps evaluate rectal bleeding, inflammation, diarrhea, lower abdominal pain, and other symptoms involving the rectum and sigmoid colon.
Medically Reviewed by Dr. Bharat Pothuri, MD, FACG | Updated 03-24-2026
Flexible sigmoidoscopy is a procedure that uses a thin, flexible camera to examine the rectum and lower part of the colon, called the sigmoid colon.
It is more targeted than a full colonoscopy and may be recommended when symptoms appear to involve the lower colon or rectum.
The exam allows your GI doctor to see the lower colon lining directly. If inflammation, ulcers, abnormal tissue, or small polyps are seen, biopsies or treatment may be performed when clinically appropriate.
A doctor may recommend flexible sigmoidoscopy to evaluate symptoms or findings that may come from the rectum, sigmoid colon, or lower portion of the colon.
The exam can help identify bleeding sources in the rectum or lower colon.
Lower-colon inflammation or irritation may be reviewed with direct visualization and biopsy when needed.
Symptoms involving the lower abdomen, rectum, or bowel movements may need a targeted exam.
Flexible sigmoidoscopy may help evaluate ulcerative colitis, proctitis, or other inflammatory changes.
Findings that suggest lower-colon disease may need direct exam and sampling.
Patients with known lower-colon conditions may need monitoring or treatment planning.
Flexible sigmoidoscopy can help identify conditions affecting the rectum and lower colon.
The exam may show inflammation, ulcers, or irritation in the lower colon or rectum.
It can help locate causes of visible blood, rectal bleeding, or irritation.
Small polyps or abnormal tissue may be seen, sampled, or treated when appropriate.
Tissue samples may help confirm inflammation, infection, or other lower-colon problems.
Flexible sigmoidoscopy checks the rectum and sigmoid colon. Colonoscopy examines the entire colon and may be better for screening or symptoms that could come from higher in the colon.
Sigmoidoscopy focuses on the area where many rectal and lower-colon symptoms begin.
It does not examine the entire colon, so a colonoscopy may still be recommended in some cases.
Some flexible sigmoidoscopies are performed without full sedation, while others use sedation for comfort.
Follow the bowel preparation instructions given by your care team. Preparation may include enemas, diet changes, medication review, or fasting instructions.
Tell your doctor about blood thinners, diabetes medicines, allergies, pregnancy, and major health conditions.
Transportation rules depend on whether sedation is used. If sedation is planned, arrange for an adult to drive you home.
Mild bloating, gas, or cramping can happen temporarily. Follow-up depends on findings and whether biopsies were taken.
Watch your GastroDoxs procedure instructions before your visit and follow the written preparation guide from your care team.
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Watch this overview in the bottom half of the page to understand how sigmoidoscopy is performed, how to prepare, and what to expect afterward. Always follow the personalized instructions from your GastroDoxs care team regarding bowel preparation, medications, arrival time, and recovery planning.
| Want procedure-day details? | Review the full guide for preparation, bowel cleansing instructions, what happens during sigmoidoscopy, recovery expectations, and how results are reviewed after the procedure. Read what to expect during sigmoidoscopy. |
| Ready to discuss sigmoidoscopy? | If you have rectal bleeding, changes in bowel habits, unexplained abdominal symptoms, or have been referred for lower gastrointestinal evaluation, review appointment and consultation options. See sigmoidoscopy scheduling options. |
Flexible sigmoidoscopy is a procedure that uses a thin, flexible camera to examine the rectum and lower part of the colon, called the sigmoid colon.
A doctor may recommend it for rectal bleeding, chronic diarrhea, lower abdominal pain, inflammation, abnormal imaging, abnormal stool tests, or follow-up of known lower-colon disease.
It examines the rectum and sigmoid colon. It does not examine the entire colon, which is why colonoscopy may be recommended when a full evaluation is needed.
Flexible sigmoidoscopy checks the lower colon and rectum. Colonoscopy examines the entire colon and can be more appropriate for screening or symptoms that may come from higher in the colon.
Blood in the stool should be evaluated promptly. Seek emergency care for heavy bleeding, dizziness, weakness, severe pain, or black stools. A GI evaluation can determine whether sigmoidoscopy, colonoscopy, or another test is needed.
Sigmoidoscopy may be used when symptoms appear limited to the rectum or lower colon, when a shorter targeted exam is appropriate, or when the doctor wants to evaluate known lower-colon disease.
Most patients feel pressure, cramping, or gas rather than severe pain. Sedation needs vary by patient, procedure plan, and medical history.
Yes. Preparation usually focuses on cleaning the lower colon and may include enemas, diet instructions, or other prep steps based on your doctor’s instructions.
Some flexible sigmoidoscopies are done without full sedation, while others may use sedation for comfort. Your care team will explain the plan before the procedure.
The exam itself is usually brief, often around 10 to 20 minutes. Total visit time may be longer because of check-in, preparation, recovery, and discharge instructions.