Blood in the stool is one of the most common signs of cancer of the colon or rectum, known as colorectal cancer. Other signs may include abnormally thin stools, changes in bowel habits, persistent abdominal pain, unexplained weight loss and anemia due to internal bleeding. However, other conditions can also lead to bloody stools, including anal tears and hemorrhoids. These often leave bright red fresh blood on the stool or toilet tissue, while a dark, tar-like appearance suggests bleeding higher up in the digestive tract.

Colon cancer and rectal cancer are increasingly being diagnosed among younger adults. The U.S. Preventive Services Task Force and the American Cancer Society now recommend that adults at average risk should start colorectal cancer screening at age 45 (lowered from age 50). People at increased risk, including those with a family history or an inherited condition known as Lynch syndrome, can benefit from even earlier screening.

Options include a colonoscopy every 10 years, flexible sigmoidoscopy every five years or stool tests every year. A colonoscopy uses a flexible lighted instrument to view the entire colon, while a sigmoidoscopy views the lower section. Stool tests, such as FIT (fecal immunochemical test) or Cologuard, look for blood or abnormal DNA in a sample collected at home. An abnormal test result should be followed by a colonoscopy. A colonoscopy is the “gold standard,” but it requires a special diet and preparation to empty your bowels. Stool tests are much simpler and also effective—the best test is the one that actually gets done!