Gastrointestinal (GI) bleeding is blood loss from anywhere in the digestive tract, from the food pipe to the anus. It shows as black tarry stool, vomited blood or coffee-ground vomit when the source is high up, and as red blood from the bottom when it is low down. The NIDDK says acute GI bleeding begins suddenly and can be severe; vomiting blood or passing black stool with dizziness, fast breathing or a racing pulse is an emergency, so call 112.
What is gastrointestinal bleeding, and what is the difference between upper and lower GI bleeding?
GI bleeding is any bleeding that starts in the digestive tract, and doctors split it by where it comes from. The NIDDK defines upper GI bleeding as bleeding from the oesophagus, stomach or the upper duodenum (the first part of the small intestine), and lower GI bleeding as bleeding from the large intestine or anus; bleeding from the rest of the small intestine, the jejunum and ileum, is called small bowel bleeding. Upper GI bleeding is the most frequent of the three.
GI bleeding is a sign of another condition, not a disease on its own. The NIDDK says it "signals a complication of another disease or condition", which is why the hospital's job is to find the cause as well as stop the blood. In the United States it leads to more than 1.5 million health care visits a year.
It also varies in speed. The NIDDK describes acute bleeding, which "begins suddenly and may sometimes be severe", and chronic bleeding, "light bleeding that can last a long time or may come and go". Cleveland Clinic adds two useful words: occult bleeding, too small to see and found only on a stool test or a low blood count, and overt bleeding, which you can see as blood in vomit or stool. Chronic or occult bleeding causes iron-deficiency anaemia over months; acute bleeding can cause shock within hours. Both need a doctor, but only the second needs an ambulance.
What are the signs of GI bleeding?
Blood that has passed through the stomach and gut turns black; blood from low down stays red. The NIDDK lists black or tarry stool, red blood mixed with stool, bright red blood in vomit, and vomit like coffee grounds, plus cramps, faintness and breathlessness.
| Sign | Medical name | What it looks like | Usual source |
|---|---|---|---|
| Black stool | Melaena | Black, sticky, tar-like, very smelly | Upper GI (stomach, duodenum) |
| Vomiting blood | Haematemesis | Bright red, or dark brown like coffee grounds | Upper GI (oesophagus, stomach) |
| Red blood from the bottom | Haematochezia | Red blood on stool, in the pan or as clots | Lower GI (colon, rectum, anus) |
| Hidden blood | Occult bleeding | Nothing visible; found on a stool test or as anaemia | Anywhere |
The NHS notes iron tablets and dark foods can blacken stool and beetroot can redden it, so colour alone is not proof.
Call 112 or go straight to an emergency department if someone vomits blood or coffee-ground material, passes black tarry stool, or bleeds heavily from the bottom (toilet water red, large clots), especially with faintness, confusion, fast breathing, cold clammy skin, a racing pulse or stomach pain. The NIDDK says these are signs of shock, which is "life-threatening". Do not drive yourself, the NHS says; get a lift or call an ambulance.
Slow bleeding is quieter: the NIDDK says it causes anaemia; the NHS says see a GP if blood in the stool lasts three weeks.
What causes upper GI bleeding?
Peptic ulcers, gastritis and oesophageal varices cause most upper GI bleeding, and in India varices from liver disease are a larger share than in Western series. The NIDDK lists the upper causes: peptic ulcers, most often from Helicobacter pylori infection, NSAID painkillers or blood thinners; gastritis, linked to the same three plus alcohol; oesophagitis from acid reflux; varices, enlarged veins in the oesophagus or stomach caused mainly by cirrhosis; Mallory-Weiss tears from forceful vomiting; and tumours of the oesophagus or stomach. The NHS names H. pylori and regular anti-inflammatory painkillers such as ibuprofen as the two main causes of stomach ulcers, with smoking and older age adding risk.
Two Indian endoscopy series show how the mix differs by region. Mahajan and Chandail, in the Journal of Mid-life Health in 2017, reviewed 1,270 patients aged 40 and over at Government Medical College, Jammu. Portal hypertension from liver disease accounted for 53.6% of cases, oesophageal varices alone for 43.5%, peptic ulcers for 17.6%, gastric erosions for 15.2% and stomach cancer for 2.4%. Of the patients with varices, 67% had alcoholic liver disease. In-hospital mortality was 5.8%, almost all from variceal bleeding.
An audit of 50 patients at SSG Hospital, Baroda, in Clinics and Practice in 2011, found acute erosive gastritis in 34%, varices in 24%, peptic ulcer in 22% and reflux oesophagitis in 18%. The Jammu authors note that series from eastern, western and coastal India found ulcers and other non-variceal causes more often, so the local share of alcohol-related liver disease shapes the picture.
What causes lower GI bleeding?
Piles and anal fissures are the commonest causes of a little bright red blood; diverticular disease, colitis, polyps and bowel cancer cause the rest. The NIDDK lists diverticular disease, haemorrhoids or anal fissures, polyps, benign tumours or cancer of the colon or rectum, and colitis from reduced blood flow, inflammatory bowel disease or infection. In the small bowel it adds angiodysplasia (abnormal blood vessels), Crohn's disease, NSAID damage and tumours.
The NHS matches the pattern of bleeding to likely causes:
- Bright red blood with pain on passing stool, itching or a lump: piles (haemorrhoids).
- Bright red blood with sharp pain, often after constipation: anal fissure, a small tear.
- Bright red blood without pain: anticoagulants or aspirin, or angiodysplasia.
- Bloody diarrhoea with cramps and bloating: inflammatory bowel disease.
- Bloody diarrhoea with slime and nausea or vomiting: gut infection.
- Blood with a changed bowel habit for three weeks, looser stool or slime: polyps or early bowel cancer.
- Black or very dark stool with tummy pain: bleeding from the stomach, possibly an ulcer.
The NHS is clear that bleeding from the bottom can be a sign of bowel cancer, that cancer is easier to treat when found early, and that you should not diagnose yourself. A GP will examine the rectum, may ask for a stool sample, and refers on for a camera test. A gastroenterologist is the specialist, and HealthFinder lists colonoscopy prices by city.
What happens in hospital for GI bleeding?
The hospital stabilises you first, then finds the bleed with a camera test and usually treats it in the same procedure. MedlinePlus says the first steps for a serious bleed can include blood transfusion, intravenous fluids and medicines. The NIDDK says blood tests show how severe the bleeding is and whether you are anaemic; MedlinePlus lists a complete blood count, platelet count and clotting tests. HealthFinder lists CBC test prices by city.
The key test for a suspected upper bleed is an upper GI endoscopy: the NIDDK describes a thin lighted tube passed through the mouth to see the oesophagus, stomach and duodenum, take biopsies and, in some cases, treat active bleeding there and then. In the Baroda audit every patient was scoped within 24 hours. For a suspected lower bleed, a colonoscopy views the rectum and the entire colon. If neither finds the source, the NIDDK lists capsule endoscopy (a swallowed camera), CT angiography, a radionuclide scan or angiography, which can also deliver material to stop the bleed.
Through the endoscope, the NIDDK says doctors can inject medicine into the bleeding site, burn and seal the vessel, close it with a band or clip, or spray a powder or gel. For an ulcer the NHS then gives antibiotics for H. pylori and a proton pump inhibitor, for one week to two months. Surgery is reserved for severe bleeding that does not stop. HealthFinder lists endoscopy prices and hospitals by city; for an active bleed, go to the nearest hospital with an endoscopy unit.
Who is at risk of GI bleeding?
Anyone can have a GI bleed, but painkillers, blood thinners, alcohol, smoking, H. pylori infection and age raise the risk. The NIDDK says the risk rises with age and with any condition that can cause bleeding. It singles out NSAIDs, over the counter or prescribed, and warns that blood thinners raise the risk further, especially taken with NSAIDs or aspirin or after a previous bleed. The NHS lists aspirin, anti-inflammatory painkillers such as ibuprofen and anticoagulants among the causes of vomiting blood.
- NSAIDs and aspirin: the NHS names regular anti-inflammatory painkillers, with H. pylori, as the two main causes of stomach ulcers.
- Blood thinners: warfarin, apixaban and other anticoagulants, which the NHS lists as a cause of painless bright red bleeding.
- Alcohol: linked to gastritis by the NIDDK, and to the cirrhosis behind varices; 67% of variceal bleeders in the Jammu series had alcoholic liver disease.
- Smoking: raises ulcer risk, per the NHS; 28% of the Baroda patients smoked.
- H. pylori infection: the main infectious cause of ulcers, which the NHS says also raises stomach cancer risk if untreated.
- Liver disease: cirrhosis from any cause produces varices, the deadliest upper source in the Jammu series.
- Older age: the NIDDK says the chance of GI bleeding rises as you get older.
The NHS advice on painkillers is simple: do not take anti-inflammatory painkillers such as ibuprofen regularly without speaking to a doctor first, and tell the doctor about every medicine, including over-the-counter ones, if you have ever had an ulcer or a bleed.
How can GI bleeding be prevented?
Prevention means removing the cause: stop or replace NSAIDs, treat H. pylori, cut alcohol, stop smoking and keep any gut condition under control. The NIDDK's advice for people who have had a bleed is to avoid NSAIDs, to drink no alcohol at all if you have oesophageal varices from cirrhosis, to quit smoking, which it says may help prevent or treat peptic ulcers, and to increase fibre if the cause was diverticular disease or piles. Cleveland Clinic adds: use NSAIDs and aspirin only when necessary and get checked for H. pylori if at risk.
For an ulcer that has bled, the NHS treatment is itself the prevention: antibiotics clear H. pylori, a proton pump inhibitor heals the lining, and the doctor stops or changes the painkiller that caused it. The NHS suggests smaller meals and an evening meal three to four hours before bed, but the NIDDK notes diet has not been shown to cause or prevent ulcers.
If you take a blood thinner for a heart or clotting condition, do not stop it on your own; the NIDDK says to discuss all medicines, including supplements, with the doctor, who may change them or add a protective drug. Cleveland Clinic says most people recover fully from a GI bleed, though the gut may take a few months to heal, and bleeds can come back, so keep the follow-up appointment even if you feel well. This guide is general information from the sources listed below, not medical advice; a registered doctor makes decisions with you.
