If you notice blood in your toilet bowl or on your toilet paper after a bowel movement, you're likely to be concerned. There are many reasons your stool could contain blood, and while most causes are fairly innocuous, blood can sometimes indicate a serious condition.
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Red Foods: A Possible Culprit
Before you start panicking, it's worth taking a moment to recall what you've eaten recently. "There are certain red foods that may cause the appearance of blood," says Daniela Jodorkovsky, MD, director of the Center for Gastrointestinal Motility and Physiology at the Columbia University Medical Center, New York City. "This includes beets, red Jell-O, anything with a lot of red food coloring or tomato juice."
Watermelon can also turn your stool red, as can cranberries, whereas black licorice, blueberries or eating a lot of dark, leafy veggies can cause your stool to appear darker than usual.
Then there are the foods that cause irritation, such as extremely spicy peppers. "The anal tissue can 'feel the burn,' and then get irritated, which can cause bleeding, either directly, or by overly aggressive wiping," says Donald Ford, MD, a family medicine physician at the Cleveland Clinic, Mayfield Heights, Ohio.
Constipation May Be to Blame
If you haven't eaten anything out of the ordinary recently, you might consider another cause for blood in your stool: constipation. If you've had trouble passing bowel movements, Dr. Ford says there's a possibility that the hard stool may be irritating your anal tissue on its way out.
"Seeing blood in the stool is always alarming," Dr. Ford says. "I would never turn a patient away if they came in with that concern. However, most occurrences are nothing to worry about." Benign, treatable conditions including hemorrhoids (swollen veins in your anus or lower rectum, says Harvard Health Publishing) and anal fissures (small tears in the lining of your anus, explains University of Iowa Hospitals & Clinics) can both cause bleeding.
Read more: What Causes Itching In the Anal Area?
Is It More Serious?
If you're not constipated and haven't eaten anything red or irritating, the blood in the toilet could be a sign of a digestive tract issue.
Taking a closer look at the specific color of the blood before you flush can help determine the source of the bleeding, according to the Cleveland Clinic. For example, bright red stool could mean that the bleeding is coming from lower in your digestive tract, such as your colon or rectum, whereas darker red or maroon stool could indicate bleeding further up your digestive tract, in your small intestine.
Black or tar-like stool could mean the bleeding is coming from your stomach and could possibly be a sign of ulcers, says the U.S. National Library of Medicine.
In some cases, blood in your stool could indicate inflammatory bowel disease, such as Crohn's disease or ulcerative colitis, according to the Mayo Clinic. In these cases, the blood is usually accompanied by pain and cramping, fever or diarrhea.
If your doctor decides to run a test on your stool to identify microscopic amounts of blood (called a "fecal occult blood test," according to Mayo Clinic), Dr. Ford and Dr. Jodorkovsky point out that certain things can cause false positives or false negatives. These include red meat, turnips, broccoli, horseradish and vitamin C supplements. It's important to avoid these foods and supplements for several days before the test.
Could It Mean Colon Cancer?
Because there are so many potential causes for blood in the stool — most of which are benign — it's better not to jump to the conclusion that you have cancer. Having said that, consistent bleeding or dark and tarry stool accompanied by changes in your bowel habits, or very narrow stool, could be a sign of colon cancer, according to the American Cancer Society.
If you're experiencing pain, weakness or fatigue in addition to bloody stool, it's important to tell your doctor. Further tests, such as colonoscopies or CT scans, could help you get to the bottom of what you're seeing in the toilet bowl.
Read more: The Best Diet Pre-Colonoscopy
Is This an Emergency?
- Cleveland Clinic: "Rectal Bleeding"
- American Cancer Society: "Signs and Symptoms of Colorectal Cancer"
- Mayo Clinic: "Inflammatory Bowel Disease (IBD)"
- Harvard Health Publishing: "Hemorrhoids and What to Do About Them"
- U.S. National Library of Medicine: "Black or Tarry Stools"
- Mayo Clinic: "Fecal Occult Blood Test"
- Daniela Jodorkovsky, MD, director, Gastrointestinal Motility & Physiology and Program, and director, Gastroenterology Fellowship Program, Division of Digestive and Liver Diseases, Columbia University Medical Center, New York City
- Donald Ford, MD, MBA, family medicine physician, Cleveland Clinic, Mayfield Heights, Ohio
- University of Iowa Hospitals & Clinics: "Stools With Blood"