When Should I Be Concerned About Blood in My Stool?

Medically Reviewed on 4/13/2022

What is blood in the stool?

Stool that is bright red, maroon colored, or black may be a sign of concern. It can be a symptom of many disorders some of which may be serious.
Stool that is bright red, maroon colored, or black may be a sign of concern. It can be a symptom of many disorders some of which may be serious.

It is important to recognize the signs of blood in the stool early. Stool that is bright red, maroon colored, or black may be a sign of rectal bleeding. Several conditions can cause rectal bleeding, such as hemorrhoids, colon cancer, and polyps. 

Not all red or black stool indicates the presence of blood. Certain foods can affect the color of your stool. Tomatoes, beets, and cranberries can all make stool look red, as can red food dye. Blueberries, black licorice, and dark leafy vegetables can all turn stool black.

Many causes of rectal bleeding will either resolve on their own or can be treated by a doctor.

Signs and symptoms of bloody stool

Pay attention to the color of your stool and whether it is mixed into the stool or covering it. This may be important information that helps your doctor make a diagnosis. 

All of the following may indicate rectal bleeding:

  • Dark blood in the stool
  • Bright-red blood mixed with or covering the stool
  • Black or tarry (resembling the color of tar) stool
  • Bright-red bloody vomit
  • Vomit that resembles coffee grounds

Bright-red stool may indicate that blood is coming from the rectum or lower digestive tract. Darker blood may suggest that it is coming from the upper digestive tract.

Abdominal cramps may indicate that blood in the stool is also irritating the stomach.

Causes of blood in the stool

Many things can cause blood in the stool. Common causes of rectal bleeding include:


Hemorrhoids are swollen blood vessels in the anus or rectum. They are the most common cause of rectal bleeding and are often related to constipation, pregnancy, heavy lifting, obesity, and diarrhea. They typically do not produce pain.

Anal fissures

Anal fissures are tears in the lining of the anus. They can result from constipation, diarrhea, or inflammation. They frequently cause pain during and after bowel movements.


Proctitis is the inflammation of the rectum’s lining. It may be caused by an infection, radiation therapy, some medications, or inflammatory bowel disease.

Colon polyps

Polyps are growths in the lining of the large bowel. Most do not cause symptoms. However, they may turn into colon cancer if left untreated.

Colon cancer

It is important to catch colon cancer early when it can still be treated. It may or may not produce rectal bleeding. Other symptoms of colon cancer include.

Additional Blood in Stool Causes 

Several other disorders may cause rectal bleeding, including:


Inflammatory Bowel Disease (IBD) Causes, Symptoms, Treatment See Slideshow

When to see the doctor for blood in the stool

Continuous rectal bleeding, large quantities of blood in the stool, or black or tarry stool can all be symptoms of serious diseases. In addition, the presence of a fever or excessive weakness combined with bloody stool requires a visit to the doctor.  

Diagnosing blood in the stool

A doctor will need to locate which area of the gastrointestinal tract is causing the bleeding. In order to diagnose the cause of blood in the stool, your doctor may perform one or more of the following tests:

  • Blood test
  • Stool sample
  • Colonoscopy, where a camera is inserted into the colon
  • Endoscopy, where a camera is inserted through the mouth or rectum
  • Capsule endoscopy, where a camera is swallowed 

Treatments for blood in the stool

While some causes of blood in the stool may resolve on their own, your doctor may decide on an active treatment to stop the bleeding. 

The most common method of treatment is endoscopy. In addition to being a diagnostic tool, it can be used to introduce a needle to inject chemicals or a cauterization device, which is used to burn a part of the body to close it or remove it.

Medication can also be used to control the recurrence of bleeding. Surgery may also be required to remove hemorrhoids or polyps.

What does green stool mean? Stool color chart

The normal color of the stool is brown, although green or greenish stool is also considered normal. The most common causes of green stool include

  • Eating green veggies such as spinach and kale
  • Ingesting green food coloring
  • Taking iron supplements

Sometimes during diarrhea when the food moves through the intestine rapidly, there isn’t enough time for the bile to break down the food completely. This may also cause green stools.

Stool color chart

Stool Color Changes 

  Color     Potential Cause      What to Do   
  Black    Gastrointestinal (GI) bleeding     It's an emergency 
  Black   Iron, bismuth   Cannot assume this to be the reason for the stool color 
  Maroon     GI bleeding    This is an emergency 
  Red   Hemorrhoids   Consult a physician 
  Red   Inflammatory bowel disease   Consult a physician 
  Red   Infection, diverticular bleed   Consult a physician 
  Red   Tumor, rapid upper GI bleeding   Consult a physician 
  Green   A diet high in green vegetables   Consult a physician 
  Green   Associated with diarrhea   Consult a physician 
  Green   Normal color    Consult a physician 
  Brown   Normal color    Nothing 
  Yellow    Diseases of the pancreas   Consult a physician 
  Yellow    Celiac disease, cystic fibrosis    Consult a physician 
  Yellow   Giardia infection    Consult a physician 
  Clay, pale yellow or white     Liver or biliary disease    Lack of bile in the stool 

Which foods can change the color of stools?

Foods can play a major role in changing the color of stools, which include

  • Green leafy vegetables such as spinach and kale (green)
  • Green food coloring used in drinks or ice pops (green)
  • Iron supplements (green or black)
  • Gluten-rich foods such as wheat, barley or rye (yellow)
  • Bread, pasta and cookies (yellow)
  • Barium (black)
  • Black licorice (black)
  • Blueberries (black)
  • Beets (red)
  • Tomato soup (red)
  • Gelatin dessert (red or orange)
  • Red drinks (red)
  • Carrots (orange)
  • Winter squash (orange)
  • Pumpkin (orange)
  • Sweet potatoes (orange)
  • Sodas (orange)
  • Candy (orange)

What causes a color change in the stools?

Some common causes of color change in the stools include

What are the symptoms associated with stool color changes?

Symptoms associated with the stool color may be due to an underlying condition. In many cases, there may be no symptoms at all. Accompanying symptoms include the following

When should I seek medical care for stool color changes?

If the stool color changes are due to changes in the diet, it will resolve on its own. If there’s a persistent change in the color of the stool, you should seek immediate medical attention. 

Additionally, contact a physician if you observe the following symptoms

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Medically Reviewed on 4/13/2022
American Cancer Society: "Colorectal Cancer Signs and Symptoms."

American Society for Gastrointestinal Endoscopy: "Understanding Minor Rectal Bleeding."

John Hopkins Medicine: "Health: Gastrointestinal Bleeding or Blood in the Stool."

University of Iowa Hospitals & Clinics: "Stools with blood."

Medscape Medical Reference