Colonoscopy is an imaging test performed to diagnose any abnormalities or changes in the rectum or the colon (large intestine). It is a minimally invasive procedure. Colonoscopy is done with the help of a colonoscope, which is a flexible, long tube with a tiny video camera placed at the tip of the colonoscope. The colonoscope is inserted into the patient's rectum and the doctor is able to see the in the colon and rectum very clearly. The colonoscope is very flexible in nature and can go through the entire length of the colon. It is a safe procedure that helps in diagnosing various problems at an early stage. It is possible to remove polyps or some other abnormal tissues easily with the colonoscope during the procedure, if needed. Colonoscopy is sometimes combined with biopsies, which are helpful for the doctor to take a biopsy tissue sample from the rectum or colon for further detailed analysis.