Bloody Stool

What is bloody stool?

Blood in the stool is an abnormal, potentially critical condition in which there is blood mixed in with a bowel movement or feces. The blood can arise from anywhere along the digestive tract, from the mouth to the anus. Bloody stool is often a sign of gastrointestinal bleeding due to injury or disease. Stools that contain bright red or maroon-colored blood may be referred to as hematochezia, while melena is used to describe black, tarry, and smelly stools. Bloody stool can occur in all age groups and populations.

Blood in the stool can appear in a variety of forms. There may be small amounts of bright red blood that is mixed inside the stool or that shows up on toilet paper after wiping the anus. Visible blood clots can also be present. Blood in the stool is sometimes accompanied by open bleeding from the rectum (rectal bleeding). Blood in the stool can be in such small quantities that it cannot be seen by the naked eye but can be detected by stool tests. This is called fecal occult blood, which may indicate a serious condition.

Many other symptoms can occur with blood in the stool depending on the cause of the bleeding. Symptoms often involve the gastrointestinal system but can involve other body systems as well. It is important to talk with your health care professional about any other symptoms you are experiencing.

What other symptoms might occur with bloody stool?

Depending on the underlying disease, disorder or condition, bloody stool may occur with other symptoms including:

 Serious symptoms that might indicate a life-threatening condition

In some cases, bloody stool may occur with other symptoms that might indicate a serious or life-threatening condition that should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, are exhibiting any of these life-threatening symptoms:

  • Change in level of consciousness

  • Confusion and disorientation

  • Difficulty breathing

  • Dizziness

  • Fainting

  • High fever (higher than 101 degrees Fahrenheit)

  • Rapid pulse

  • Rigid, board-like abdomen

  • Severe abdominal pain

  • Vomiting blood or black material (resembling coffee grounds)

  • Weakness (loss of strength)

What causes bloody stool?

Blood in the stool can indicate a relatively mild condition, such as hemorrhoids or constipation, or it can be due to a serious, even life-threatening condition, such as esophageal varices or colon cancer. Certain medications, such as aspirin, can also cause bloody stool.

Black, tarry stools usually indicate that the blood is coming from the upper gastrointestinal tract (esophagus, stomach and duodenum), while red or maroon-colored stools often originate from bleeding in the lower gastrointestinal tract (colon, rectum and anus). Bloody stool that is associated with dizziness, diarrhea, or vomiting blood should be immediately evaluated in an emergency setting. However, a diagnosis of the cause of blood in the stool can be delayed or missed because tiny amounts of blood may not be noticeable for long periods of time.

Upper gastrointestinal tract causes of bloody stool

Causes of bloody stool related to the upper gastrointestinal tract include:

Lower gastrointestinal tract causes of bloody stool

Causes of bloody stool related to the lower gastrointestinal tract include:

Other causes of bloody stool

Bloody stool can be caused by:

Serious or life-threatening causes of bloody stool

Any type of blood in the stool should be evaluated by a health care professional. In some cases, bleeding may accompany a serious or life-threatening condition including:

  • Bleeding peptic ulcer

  • Bowel obstruction

  • Food poisoning

  • Ruptured esophageal varices

  • Severe abdominal trauma

What are the potential complications of bloody stool?

Over time, bloody stool can lead to serious complications including:

  • Anemia

  • Severe blood loss

  • Shock 
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jan 3
View All Digestive Health Articles
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Bloody or tarry stools. Medline Plus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/ency/article/003130.htm.
  2. Bleeding esophageal varices.  Medline Plus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/ency/article/000268.htm.
  3. Gastrointestinal bleeding. Medline Plus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/gastrointestinalbleeding.html.
  4. Lower Gastrointestinal Bleeding. Medscape. http://emedicine.medscape.com/article/188478-overview.