DefinitionBloody stools often are a sign of an injury or disorder in the digestive tract. Your doctor may use the term "melena" to describe black, tarry, and foul-smelling stools or "hematochezia" to describe red- or maroon-colored stools.
Alternative NamesStools - bloody; Hematochezia; Melena; Stools - black or tarry
ConsiderationsBlood in the stool may come from anywhere along your digestive tract, from mouth to anus. It may be present in such small amounts that you cannot actually see it, and it is only detectable by a fecal occult blood test.When there is enough blood to change the appearance of your stools, the doctor will want to know the exact color to help find the site of bleeding. To make a diagnosis, your doctor may use endoscopy or special x-ray studies.Black stool usually means that the blood is coming from the upper part of the gastrointestinal (GI) tract. This includes the esophagus, stomach, and the first part of the small intestine. Blood will typically look like tar after it has been exposed to the body's digestive juices as it passes through the intestines.Maroon-colored stools or bright red blood usually suggests that the blood is coming from the lower part of the GI tract (large bowel, rectum, or anus). However, sometimes massive or rapid bleeding in the stomach causes bright red stools.Eating black licorice, lead, iron pills, bismuth medicines like Pepto-Bismol, or blueberries can also cause black stools. Beets and tomatoes can sometimes make stools appear reddish. In these cases, your doctor can test the stool with a chemical to rule out the presence of blood.Bleeding in the esophagus or stomach (such as with peptic ulcer disease) can also cause you to vomit blood.
Common CausesThe upper part of the GI tract will usually cause black stools due to:Abnormal blood vessels (vascular malformation)A tear in the esophagus from violent vomiting (Mallory-Weiss tear)Bleeding stomach or duodenal ulcerInflammation of the stomach lining (gastritis)Lack of proper blood flow to the intestines (bowel ischemia)Trauma or foreign bodyWidened, overgrown veins (called varices) in the esophagus and stomachThe lower part of the GI tract will usually cause maroon or bright red, bloody stools due to:Anal fissuresBowel ischemia (when blood supply is cut off to part of the intestines)Colon polyps or colon cancerDiverticulosis (abnormal pouches in the colon)Hemorrhoids (common cause)Inflammatory bowel disease (such as Crohn's disease or ulcerative colitis)Intestinal infection (such as bacterial enterocolitis)Small bowel tumorTrauma or foreign bodyVascular malformation (abnormal collections of blood vessels called arteriovenous malformations or AVMs)
Call your health care provider ifCall your doctor immediately if you notice blood or changes in the color of your stool. Even if you think that hemorrhoids are causing the blood in your stool, your doctor should examine you to make sure that there is no other, more serious cause present.In children, a small amount of blood in the stool is usually not serious. The most common causes are constipation and milk allergies. However, it is still worth reporting to your doctor, even if no evaluation is needed.
What to expect at your health care provider's officeYour doctor will take a medical history and perform a physical examination, focusing on your abdomen and rectum.The following questions may be included in the history to better understand the possible causes of your bloody or dark stools:Are you taking blood thinners (aspirin, warfarin, clopidogrel, Aggrenox) or NSAIDs (ibuprofen, naproxen)?Have you had any trauma to the abdomen or rectum, or have you swallowed a foreign object accidentally?Have you eaten black licorice, lead, Pepto-Bismol, or blueberries?Have you had more than one episode of blood in your stool? Is every stool this way?Have you lost any weight recently?Is there blood on the toilet paper only?What color is the stool?When did it develop?What other symptoms are present -- abdominal pain, vomiting blood, bloating, excessive gas, diarrhea, or fever?Treatment depends on the cause and severity of the bleeding. For serious bleeding, you may be admitted to a hospital for monitoring and evaluation. If there is massive bleeding, you will be monitored in an intensive care unit. Emergency treatment may include a blood transfusion.The following diagnostic tests may be performed:AngiographyBarium studiesBleeding scan (nuclear medicine)Blood studies, including a complete blood count ( CBC) and differential, serum chemistries, clotting studiesColonoscopyEsophagogastroduodenoscopy or EGDStool cultureTests for the presence of Helicobacter pylori infectionX-rays of the abdomenTREATMENTIf you have passed a lot of blood, you may need emergency treatment, which can include:Blood transfusionsFluids through a veinInterventional radiography embolization (a procedure to block the blood vessels that may be bleeding)Medications to decrease stomach acidPossible surgery if bleeding does not stop
PreventionFor information about preventing the different causes of bloody or tarry stools, see:Bleeding esophageal varicesBowel ischemiaColon cancerDiverticulosisPeptic ulcers
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