Black or tarry stool and bright red blood

These pages describe stool color as a clue for where a clinician looks. They do not name one person's cause. ahem has not examined anyone and does not sell a treatment. The hemorrhoid description of small amounts of bright red blood is on when rectal bleeding should be checked.

MedlinePlus reviewed its black-or-tarry-stool page on April 27, 2026. Opened October 29, 2026, it says black or tarry stools with a foul smell are a sign of a problem in the upper digestive tract. It most often indicates bleeding in the esophagus, stomach, or first part of the small intestine. The page uses the word melena for that finding. It says the blood is darker because it is digested on the way through the tract. Red or fresh blood in the stool, which it also calls rectal bleeding, most often is a sign of bleeding from the lower tract: the colon, rectum, or anus.

NIDDK last reviewed its gastrointestinal bleeding symptoms page in July 2024. On the copy opened October 29, 2026, acute bleeding begins suddenly and can sometimes be severe. The symptoms it lists include black or tarry stool, dark or bright red blood mixed with stool, bright red blood in vomit, and vomit that looks like coffee grounds. The same page says chronic bleeding can leave a small amount of blood that is too small to see, which it calls occult bleeding, and that stool may sometimes be black and tarry and sometimes mixed with bright red blood.

MedlinePlus says black stool can also follow black licorice, blueberries, blood sausage, iron pills, activated charcoal, or medicines that contain bismuth. It names Pepto-Bismol as an example of a bismuth medicine. Beets and foods with red coloring can sometimes make stools look reddish. In those cases, the page says a clinician can test the stool with a chemical to check for blood. NIDDK's bleeding page does not print that food and medicine list.

A black stool on a polyp page can also be blood from a growth in the colon. That description, and the screening age those pages print, is on a colon polyp and rectal bleeding. The polyp pages and these bleeding pages are describing different places blood can come from. The color sentence here is the upper-tract description from MedlinePlus and NIDDK.

MedlinePlus says peptic ulcers are the most common cause of acute upper gastrointestinal bleeding. Its other causes of black and tarry stool include abnormal blood vessels, a tear in the esophagus from violent vomiting, loss of blood supply to part of the intestines, inflammation of the stomach lining, trauma or a foreign body, widened veins in the esophagus and stomach that it says are commonly caused by liver cirrhosis, and cancer of the esophagus, stomach, duodenum, or ampulla of Vater. It also says anticoagulant or antiplatelet medicines, which it calls blood thinners, increase the risk of gastrointestinal bleeding.

NIDDK's upper-tract list, on the page opened October 29, 2026, includes peptic ulcers, which it describes as sores on the lining of the stomach or duodenum. It says the most common causes of those ulcers are Helicobacter pylori infection and taking nonsteroidal anti-inflammatory drugs such as aspirin, ibuprofen, and naproxen, and blood thinners. It also names gastritis, esophagitis often caused by gastroesophageal reflux, enlarged veins related to cirrhosis, tears in the lower esophagus often caused by severe vomiting, and benign tumors or cancer.

For bleeding lower down, NIDDK names diverticular disease, when a small blood vessel in the wall of a pouch bursts; hemorrhoids and anal fissures; polyps, benign tumors, or cancer in the colon or rectum; and colitis, including ulcerative colitis, Crohn's disease, and infections. Those lower-tract problems have their own pages when this site has opened them. Diverticular bleeding is on diverticular disease and bleeding. Ulcerative colitis is on ulcerative colitis and rectal bleeding.

NIDDK says chronic gastrointestinal bleeding may cause a small amount of blood in the stool. If the amount is too small for the person or the doctor to see, it is called occult bleeding, and doctors can order stool and blood tests. Over time, chronic bleeding can cause anemia. On that page, anemia symptoms may include feeling tired, pale skin, and shortness of breath. If the amount of bleeding suddenly increases, NIDDK says the symptoms can become those of acute bleeding, and to seek medical help right away.

Ongoing blood loss from hemorrhoids is a separate, uncommon anemia sentence on complications the sources name. NIDDK's anemia sentence on the bleeding page is about gastrointestinal bleeding in general, including blood that never shows as a visible streak.