Many different health conditions can cause rectal bleeding. Learn more about the different causes and when you should call your doctor.

After a bowel movement, you may have noticed it: blood in your stool, in the toilet bowl, or on the toilet tissue. Or maybe your stools themselves appear red or black and tarry.

Rectal bleeding can occur with many different medical conditions. It can be common and easily treatable or may be a sign of something serious.

Learn more about what causes it and how you can get it diagnosed and treated.

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What Can Cause Blood in the Stool?

Bloody stools indicate you have bleeding in your digestive tract, which includes:

  • Esophagus
  • Stomach
  • Small intestine
  • Large intestine
  • Rectum

In some cases, food may cause your stool to look red (cranberries, tomatoes, or beets) or black (blueberries, black licorice, and dark vegetables).

Straining while making a bowel movement, such as when you’re constipated, can cause bleeding.

Many different medical conditions also may cause rectal bleeding.


Hemorrhoids are swollen or stretched veins in and around your anus.

Hemorrhoids can happen when pressure builds up in your lower rectum, which can come from many different causes:

  • Straining during bowel movements.
  • Lifting heavy objects.
  • Sitting for long periods of time.
  • Constipation or diarrhea.
  • Low-fiber diets.
  • Pregnancy or delivery.
  • Weight gains.

Hemorrhoids can occur internally, higher up in your rectum, or externally, around the lining. Depending on where they occur, they might be painless. But they also can cause pain and rectal bleeding.

Anal fissures

An anal fissure is inflammation or tearing of the lining in your lower rectum. It can cause pain and bleeding during bowel movements.

Anal fissures can occur from passing a large stool or straining to pass a stool while constipated. Repeated diarrhea and anal trauma from childbirth also can cause fissures.

Peptic ulcers

Peptic ulcers are sores that can form in the lining of the stomach or upper small intestine. They occur when the stomach’s digestive juices damage the lining of the stomach and/or the upper small intestine.

Common causes include infection with Helicobacter pylori (H. pylori) bacteria or long-term use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs).

Ulcers most often cause burning stomach pain.


The development of small pockets in the walls of your large intestine (colon) where the blood vessels enter is called diverticulosis. Diverticulitis occurs when those pouches become inflamed or infected with bacteria.

Diverticulitis can affect your bowels and cause pain. Bleeding can happen in serious cases of diverticulosis.

Crohn’s disease or ulcerative colitis

These two conditions, also known as inflammatory bowel diseases (IBD), cause inflammation and damage to your digestive tract.

Crohn’s disease can affect your entire digestive system. Ulcerative colitis involves your colon and rectum. IBD can cause many different symptoms, including rectal bleeding.


Polyps are growths in the colon or rectum. Often, polyps cause no symptoms, but large polyps can cause bleeding.

If you have large polyps that are causing rectal bleeding, call your doctor. Bleeding from large polyps may be a sign of colorectal cancer. Often, bleeding from colon cancer is invisible to the naked eye.


Rectal bleeding is a warning sign for several types of cancer, including colorectal cancer, stomach cancer, and esophageal cancer.

What Are the Symptoms of Rectal Bleeding?

Rectal bleeding symptoms include:

  • Difficulty or pain during bowel movements.
  • Bleeding during bowel movements.
  • Blood mixed with stool.
  • Black, tarry stools.
  • Pain in the rectum.
  • Dizziness or lightheadedness.

Should I Be Worried If I Have Blood in My Stool?

Rectal bleeding can happen for many different reasons, many of which are common and benign. So, don’t panic if you see blood in your stool. Still, you should call your doctor. Many different factors can cause rectal bleeding, and it’s important to find out what’s happening.

You should call your doctor if you experience other symptoms along with your rectal bleeding. Additional symptoms could be a sign of a more serious medical condition. Your doctor can run a variety of tests to see what is causing your rectal bleeding.

Depending on what is causing your symptoms, your doctor can recommend treatment options. There are a variety of treatments for the conditions that can cause rectal bleeding.

Michael Pezzone, MD, chief, Gastroenterology, UPMC Mercy, highly recommends following up with your PCP if you have rectal bleeding.

“Colon cancer is affecting younger and younger adults and can even occur in 20-year-olds when you expect to find hemorrhoids,” Dr. Pezzone says. “Everyone should be up to date with their colon cancer screening, which now begins at age 45, especially If you have a family history of colon cancer. Seventy percent of patients who develop colon cancer do so because they were not up to date with their screening.”

University of Iowa Hospitals and Clinics, Stools With Blood. Link

U.S. National Library of Medicine, Gastrointestinal Bleeding. Link

About Digestive Disorders

UPMC Digestive Health Care cares for a wide range of gastrointestinal (GI) conditions and diseases, from diagnosis to treatment. Whether your digestive condition is common or complicated, our experts can help. Upon referral from your physician, we coordinate your testing and treatment. If you have a complicated condition, we can refer you to one of UPMC’s digestive health centers of excellence. Find a GI doctor near you.