A flexible sigmoidoscopy is a test in which your doctor examines the lining of the most distal (lower) portion of your large intestine, or colon.  The test is basically an abbreviated colonoscopy.  It is similar to a colonoscopy in that the patient must prepare by cleaning out the colon, this time by using enemas without an oral laxative.  The procedure can be performed in the office and does not require sedation though this can be given if performed in the ambulatory endoscopy center.  When a complete colonoscopy is not necessary to evaluate a given symptom, a flexible sigmoidoscopy may be recommended by your doctor.