Bright Red Blood in Stool: Should I Worry?

Causes can range from hemorrhoids to cancer

Bright red or any type of blood in your stool is not normal. While it may be due to something as simple as straining to poop because of constipation, it can also be due to conditions such as hemorrhoids, a bowel infection, or even colon cancer.

Blood in the stool—whether bright red or some other shade—should always be evaluated by a healthcare provider. Though it could be caused by a condition that isn't dangerous, it is always best to have them rule out more serious causes. 

This article reviews common causes of blood in the stool and how your healthcare provider will determine why this is occurring.

Common Causes of Blood in the Stool
Verywell / Derek Abella

When to Call Your Healthcare Provider

Because the the lining of the colon has lots of blood vessels, any injury can lead to bright red rectal bleeding. Blood in the stool can be an alarming sight, and it's natural to want to clarify the reason. It's best to check with your healthcare provider, even when you're not having any pain with the bleeding.

While you should always check with your healthcare provider, some signs can be more serious than others. If you notice these signs, contact your healthcare provider immediately:

  • The bleeding is severe and won't stop.
  • Bleeding persists for more than a few days.
  • Foul-smelling stools with a coffee-grain appearance.

Seek emergency care if bloody stool is accompanied by:

  • Shallow or rapid breathing
  • Lightheadedness
  • Severe nausea
  • Fainting or loss of consciousness
  • Fever or drop in body temperature
  • Clammy and cold skin
  • Fatigue or tired feeling
  • Confusion or disorientation

These issues could be linked to serious infection or severe blood loss.

No amount of blood in the stool is normal, but some causes may be more dangerous than others. Sometimes there is blood in such small amounts that it can't be seen with the eye. In these cases, it must be identified with a test called a fecal occult test.

Color of Blood in Stool

The blood in your stool may be different colors depending upon where in your colon it is located, for example:

  • Bright red blood in your stool may indicate bleeding in the lower part of the colon.
  • Darker red blood in the stool usually means bleeding in the higher part of the colon.
  • Extremely dark or tar-like stool often indicates bleeding in the stomach.

Your healthcare provider may want to run tests based on the color of your stool.

Blood in the Stool Not Due to Cancer

Bright red blood in the stool can be a sign of multiple noncancerous conditions. Your healthcare provider can help you determine whether your bleeding is a result of one of these conditions.

Constipation

Constipation and straining to pass a large bowel movement can lead to smears of bright red blood on the toilet paper. Causes of constipation include:

  • Not drinking enough water
  • Low-fiber diets
  • Lack of exercise
  • Changes in routine
  • Eating too much dairy
  • Stress
  • Holding your bowel movements
  • Certain medications
  • Certain health conditions
  • Pregnancy

Let your healthcare provider know if you are straining to pass bowel movements. This straining can lead to tiny, uncomfortable tears in your anal tissues, called fissures. Anal sex can also sometimes cause these tiny fissures and rectal bleeding.

Hemorrhoids

Hemorrhoids are swollen blood vessels that can be inside or outside of the anus. They are a common, mostly harmless problem. However, they are fragile and can bleed, so they're the number one cause of bright red blood smears on the toilet paper.

You may or may not feel any discomfort with a hemorrhoid. Pregnancy and straining during a bowel movement are two common causes of hemorrhoids. They are easily treatable and may even resolve on their own.

Inflammatory Conditions

Certain inflammatory diseases in the colon can cause bright red or dark red blood in the stools. These include:

Colon Polyps

Colon polyps are growths on the inside wall of the colon. Most polyps are benign (noncancerous) and do not cause any symptoms.

Polyps can and do bleed, though, particularly larger ones. If your healthcare provider suspects a polyp, they will want to order a colonoscopy to investigate and remove the polyp. Untreated polyps can lead to colon cancer.

Colorectal Cancer Screening

The U.S. Preventive Services Task Force (USPSTF) recommends regular screening for colorectal cancer for adults who are 45 to 75 years old.

Bowel Infections

Untreated bowel infections, such as Escherichia coli (E. coli), can cause bloody diarrhea and abdominal pain. E. coli can stem from consuming undercooked meats or unpasteurized juice and dairy products. The infection requires antibiotic therapy.

Blood in the Stool Due to Cancer

Colon cancer can cause blood in the stool. However, in the early stages, most colon cancers do not generate any symptoms.

Fecal testing can detect the presence of hidden blood in the stool. Stool DNA tests can look for the genetic material shed by polyps or tumors.

If the visible blood in your stool is from colon cancer, it is most often from the left side of the colon (including the descending colon, sigmoid colon, or rectum). Cancer in the right side of the colon usually does not present with noticeable bleeding.

Cancer-related bleeding may vary in color, depending on the location of the cancer. Bleeding from cancer that is lower in the bowel or is in the rectum may be bright red. Blood that comes from higher up in the bowel may be dark red or black. 

Blood that is related to cancer is more consistent than blood that comes from hemorrhoids. It usually occurs regularly and gets worse over time. 

Diagnosis

Your healthcare provider will complete a physical exam to look for any visible causes of rectal bleeding, like hemorrhoids or anal abrasion. They will also take your medical history. Then, they may order tests to investigate the cause further, even if it is obvious.

Your healthcare provider might order:

  • Complete blood count (CBC): This blood test can show how much blood you may have lost.
  • Clotting time: If you take anticoagulants (blood thinners), your healthcare provider may want to check if your blood is too thin.
  • Fecal occult blood test (FOBT) or fecal immunochemical test (FIT): These stool tests check for the presence of blood.
  • Colonoscopy: In this procedure, a healthcare provider uses a scope to look inside the entire colon. This test allows the healthcare provider to see and remove any polyps in the colon lining.
  • Sigmoidoscopy: This test is similar to a colonoscopy, but looks only at the lower part of the colon, including the sigmoid colon and the rectum.
  • X-rays: Images of the lower intestinal tract may show any large abnormalities in the colon.

Following the test(s), your healthcare provider will discuss the findings with you. They may potentially order further testing if imaging found abnormalities. Based on the results, they can develop a treatment plan, as needed.

The best action you can take now is to make an appointment with your healthcare provider. Prepare for your visit by asking yourself these questions:

  • Was the blood in the stool, toilet bowl, or on the toilet paper?
  • Was the blood bright red or dark red?
  • Approximately how much blood did you see? (Keep in mind, a drop of blood in a toilet bowl will turn all of the water red.)
  • Did you have to strain to pass the bowel movement?
  • How frequently do you have bowel movements?
  • Do you have other symptoms?
  • When was your last colon cancer screening or colonoscopy?
  • Do you have a history of polyps or a family history of polyps?

Summary

Bloody stools can have many causes. Often, bleeding during a bowel movement is a clue to benign conditions, like hemorrhoids, constipation, or polyps. But sometimes, it can indicate something more serious such as an infection, intestinal disease, or cancer.

A Word From Verywell

Rectal bleeding is unsettling. If you notice bleeding when you have a bowel movement, rest assured that it is most likely due to something minor. Even so, it's essential to pay attention to the bleeding that occurs during a bowel movement, since it can sometimes be a sign of colon cancer. If you notice blood in your stool of any color, check with your healthcare provider.

Frequently Asked Questions

  • How do I stop bloody stool?

    The best way to stop bloody stool is by treating its underlying cause. Bloody stool caused by mild hemorrhoids may require little to no treatment, as some resolve themselves.

  • Are there foods that cause red stool?

    Yes, certain foods may cause stool to turn red, which can resemble blood. These include foods like red gelatin, popsicles, sports drinks, drinks that contain food dyes (like fruit punch), tomato juice or soup, beets, or any food that is made with natural or artificial red food coloring (red #40).

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Mayo Clinic. Rectal bleeding: When to see a doctor.

  2. Cleveland Clinic. Constipation.

  3. American Society for Gastrointestinal Endoscopy. Understanding minor rectal bleeding.

  4. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & causes of GI bleeding.

  5. Centers for Disease Control and Prevention. What should I know about screening?.

  6. American Academy of Family Physicians. E coli infection.

  7. American Cancer Society. Colorectal cancer signs and symptoms.

  8. Johns Hopkins Medicine. Colon cancer symptoms.

  9. Cleveland Clinic. Rectal Bleeding.

Additional Reading

By Julie Wilkinson, BSN, RN
Julie Wilkinson is a registered nurse and book author who has worked in both palliative care and critical care.