S Sigmoidoscopy is used to examine the sigmoid colon through the anus. The rectum and anus are the least invasive medical examinations that can be performed immediately on the day of the consultation. Common symptoms of these areas are changes in bowel habits, rectal bleeding, abdominal pain, and unexplained weight loss. Observe and diagnose the cause of bleeding or pain; if necessary, the doctor can use a special tool to extract the diseased tissue through the endoscope for testing, and the process only takes 15-20 minutes.