Traditionally, doctors have said most people should get their first colonoscopy around age 50. This is called screening, and it means that even healthy people at that age with no symptoms should get tested. An increasing number of younger adults are being diagnosed with colorectal cancer. So the American Cancer Society now recommends that adults get their first colonoscopy at age 45. In addition, African-Americans have an increased risk of polyps and should get tested five years earlier. Your doctor should recommend a colonoscopy when you approach 45 or 50, but you should bring it up yourself if they don't. The other exception concerns your relatives. If you have a parent, sibling or child with colorectal cancer, you should get tested at age 40 or at an age ten years earlier than the relative was when they were diagnosed. For example, if your dad was diagnosed at age 44, you should get tested at age 34. Though screening is the best way to prevent colorectal cancer or spot it early, it is also important to be vigilant for its signs.