Have Blood In Your Stool? Here’s What It Could Mean

It's scary to see blood in your stool, but there are many reasons that this can occur—and the most common ones aren't serious.

What it means when you have blood in your stool

Seeing bright red blood in your stool can be alarming, but it is highly common. What’s more, it’s usually not a sign of a serious problem.

That doesn’t mean you can or should ignore rectal bleeding. Experts agree that it’s always better to be safe than sorry and discuss any blood in your stool with your doctor to see if further evaluation is needed.

The shade of the blood can help determine where it is coming from and what is causing it, says Will Bulsiewicz, MD, a gastroenterologist in Mount Pleasant, South Carolina, and the author of Fiber Fueled. “Cherry- or fire hydrant-red blood is usually from the rectum or lower colon because it is very fresh,” he says. By contrast, dark red or maroon blood may mean you are bleeding higher up in your colon, and black or tar-like stool suggests bleeding in your stomach from an ulcer, he notes. (Here’s why blood is red in case you are curious.)

The two most common causes of bright red blood in your stool are anal fissures and internal hemorrhoids, he says. “If red blood drops into the toilet from your bottom or you find it on your underwear or when you are wiping, it is likely a hemorrhoid or fissure,” he says.

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Is it an anal fissure?

If you have pain and red blood when you have a bowel movement, it could be an anal fissure, Dr. Bulsiewicz says. These are tears in the lining of the anus (the opening where stool is passed).

Your doctor can perform a rectal exam to verify the presence of a tear, he says. “If we identify a tear, we can treat it with prescription cream, and if the bleeding completely subsides, we are done,” he says. Anal tears can occur when passing hard or bulky stool, or from other trauma to the lining of the anus. Less common causes of anal fissures are inflammatory bowel diseases or an infection.

Is it a hemorrhoid?

Hemorrhoids are swollen blood vessels in the rectum or anus that may cause bleeding and itching during a bowel movement, but they usually don’t cause pain, he says. Your doctor will perform a physical exam as well as a digital rectal exam to check for the presence of hemorrhoids and other potential sources of bleeding.

During a digital rectal exam, your doctor places a gloved and lubricated finger inside your rectum to check for any abnormal findings such as an internal hemorrhoid. Other procedures may be necessary to find the source of the bleeding.

If a hemorrhoid is causing the bleeding, eating more fiber will help make your stools softer and easier to pass, which prevents the straining that can cause or worsen hemorrhoids, Dr. Bulsiewicz says. The recommended amount of dietary fiber is 22 to 35 grams per day for adults, according to the Dietary Guidelines for Americans 2015-2020. Drinking water can help the fiber do its job. (These 12 home remedies may also offer relief from hemorrhoids.)

Taking warm sitz baths (warm, shallow water covering the hips and buttocks) and/or using certain over-the-counter creams can also help soothe and shrink hemorrhoids, but there are times when surgery, such as rubber band ligation, may be necessary. During rubber band ligation, rubber bands are placed around the base of your hemorrhoid to restrict blood flow and shrink it, he says. There are other procedures that can help remove or reduce the size of hemorrhoids, too.

Is it a polyp?

Polyps are precancerous growths in your colon that may bleed. In most cases, polyps are found during a colonoscopy procedure, but sometimes they make their presence known with rectal bleeding, he says.

“As we move away from fire hydrant red toward darker shades of red, it likely indicates something higher up in the colon such as a polyp,” Dr. Bulsiewicz says. Polyps can be removed, which should stop the bleeding and also prevent the growth from becoming cancerous.

Is it diverticulosis?

Diverticulosis is a condition that occurs when small pouches—known as diverticula—develop in the wall of the colon. If the pouches become infected and inflamed, it can cause bleeding and is known as diverticulitis. Diverticular bleeding is the most common cause of major rectal bleeding in people over 40, according to the American Society for Gastrointestinal Endoscopy.

“It can be rather dramatic, and those patients come into the emergency room and get a full workup,” says Arun Swaminath, MD, director of the inflammatory bowel disease program at Lenox Hill Hospital in New York City. This condition may be found on a routine colonoscopy, which is an examination of the entire colon with a lighted instrument, or a sigmoidoscopy, which uses a shorter tube to examine only the rectum and lower part of the colon, he says.

Is it colon cancer?

When someone sees blood in their stool, their mind often jumps to colon cancer, but the first sign of colon cancer is usually anemia, Dr. Swaminath says.

Colon cancers can cause bleeding and a loss of red blood cells, which causes anemia. Anemia is usually picked up during routine blood work. The best way to get ahead of a colon cancer diagnosis is with routine screening. The American Cancer Society now recommends that people at average risk of colorectal cancer start regular screening at age 45. Average-risk individuals do not have a personal or family history of colon cancer or any other conditions that would predispose them to the cancer. (The age was lowered due to increasing reports of colon cancer in younger individuals and millennials.) Screening might start even sooner if you have other risk factors for colorectal cancer.

Screening should be done either with a test that looks for signs of cancer in a person’s stool or with an exam that looks at the colon and rectum, such as a colonoscopy. During a colonoscopy, your doctor can see your entire colon.

“Your doctor can remove any precancerous polyps or cancers before they have spread beyond the colon itself,” Dr. Swaminath says. Before a colonoscopy, you will need to take laxatives to remove all waste so the doctor can visualize any polyps or abnormalities. (These are the best colonoscopy prep tips, according to doctors.)

There are always some outlier causes of blood in your stool as well, Dr. Swaminath says.

As a general rule, your age, background, and history can help you and your doctor determine why there is blood in your stool.

“If it is a younger person with a family history of autoimmune disease, we may think about inflammatory bowel diseases such as ulcerative colitis or Crohn’s disease,” he says. “A man who had undergone radiation for prostate cancer may experience rectal bleeding because the prostate is located behind the rectum, so the radiation may hit it and cause bleeding.”

Blood in stool: Red flags

There are some symptoms that raise suspicion when they accompany blood in the stool, Dr. Bulsiewicz points out. These can include multiple bowel movements in a row with fresh blood and unexplained weight loss. Feelings of light-headedness, weakness, or a racing heart could also suggest you are losing more blood. Make sure to bring these to your doctor’s attention, he notes.

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Denise Mann, MS
Denise Mann is a freelance health writer whose articles regularly appear in WebMD, HealthDay, and other consumer health portals. She has received numerous awards, including the Arthritis Foundation's Northeast Region Prize for Online Journalism; the Excellence in Women's Health Research Journalism Award; the Journalistic Achievement Award from the American Society for Aesthetic Plastic Surgery; National Newsmaker of the Year by the Community Anti-Drug Coalitions of America; the Gold Award for Best Service Journalism from the Magazine Association of the Southeast; a Bronze Award from The American Society of Healthcare Publication Editors (for a cover story she wrote in Plastic Surgery Practice magazine); and an honorable mention in the International Osteoporosis Foundation Journalism Awards. She was part of the writing team awarded a 2008 Sigma Delta Chi award for her part in a WebMD series on autism. Her first foray into health reporting was with the Medical Tribune News Service, where her articles appeared regularly in such newspapers as the Detroit Free Press, Chicago Sun-Times, Dallas Morning News, and Los Angeles Daily News. Mann received a graduate degree from the Medill School of Journalism at Northwestern University in Evanston, Ill., and her undergraduate degree from Lehigh University in Bethlehem, Pa. She lives in New York with her husband David; sons Teddy and Evan; and their miniature schnauzer, Perri Winkle Blu.