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Health condition · Clinically reviewed

Gastrointestinal bleeding, from resuscitation to endoscopy and interventional radiology.

Upper GI, lower GI and obscure bleeding all need the same first steps: airway, breathing, circulation, then risk stratification and endoscopy within 24 hours.

Jump to treatment
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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE CG141, BSG and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including restrictive transfusion targets, endoscopic haemostasis and interventional radiology.

Key facts

GI bleeding at a glance.

The essentials in plain English. What it is, where it comes from and how it is managed in the UK today.

  • What it is

    Bleeding anywhere from the mouth to the anus. Split into upper GI (proximal to the ligament of Treitz), lower GI and small bowel or obscure sources.

  • Upper GI causes

    Peptic ulcer disease is the leading cause. Others include oesophageal varices, Mallory-Weiss tears, oesophagitis, gastric cancer, Dieulafoy lesions and angiodysplasia.

  • Lower GI causes

    Diverticular disease, colorectal cancer, angiodysplasia, IBD, haemorrhoids, anal fissures, polyps, ischaemic colitis and radiation proctitis.

  • How it shows up

    Haematemesis or coffee-ground vomiting, melaena, haematochezia, iron deficiency anaemia or shock in severe cases.

  • Risk scoring

    Glasgow-Blatchford and AIMS65 for upper GI, Oakland for lower GI. Guides admission, endoscopy timing and disposition.

  • Foundation therapy

    Resuscitation first. Then endoscopy within 24 hours, PPI for ulcers, band ligation for varices and interventional radiology when endoscopy fails.

Why this guide matters

Speed and structure save lives.

Whatever the source, the same principles apply: resuscitate, risk-stratify and get to endoscopy inside 24 hours. The three points below shape everything else on this page.

  • Resuscitation comes first

    Airway, breathing, circulation and blood. A restrictive transfusion target of 7 to 8 g/dL improves outcomes for most non-varix upper GI bleeds.

  • Endoscopy within 24 hours

    A gastroscopy or colonoscopy inside a day finds the source, allows immediate treatment and shortens hospital stay.

  • IR when endoscopy fails

    Selective mesenteric embolisation stops bleeding in most patients where endoscopy is not enough, avoiding open surgery.

How the diagnosis is made

From first vomit or PR bleed to a definitive plan.

The steps a UK emergency department, gastroenterology unit or interventional radiologist will follow, in order.

  1. 01

    Assessing

    History and medications

    Onset, volume, character of bleeding, NSAIDs, aspirin, anticoagulants, antiplatelets, alcohol use, chronic liver disease and prior GI bleeding.

  2. 02

    Assessing

    Examination and PR

    Vital signs, stigmata of chronic liver disease, abdominal exam and a rectal examination to confirm melaena or fresh bleeding.

  3. 03

    Assessing

    Risk stratification

    Glasgow-Blatchford and AIMS65 for upper GI, Oakland for lower GI. Rockall is calculated after endoscopy.

  4. 04

    Confirming

    Bloods and cross-match

    FBC, U and Es, LFTs, coagulation, group and save, cross-match, venous gas, lactate and fibrinogen for major haemorrhage.

  5. 05

    Confirming

    Upper GI endoscopy

    A gastroscopy within 24 hours identifies the bleeding source, classifies ulcers by Forrest and allows immediate endoscopic therapy.

  6. 06

    Confirming

    Colonoscopy or CT angiography

    A colonoscopy within 24 hours for severe lower GI bleeding. CT angiography for ongoing haemorrhage where endoscopy is not diagnostic.

  7. 07

    Escalating

    Capsule and enteroscopy

    For obscure or small bowel bleeding, capsule endoscopy followed by double-balloon enteroscopy under specialist gastroenterology.

Typical timeline: from arrival to endoscopic haemostasis within 24 hours.

Symptoms

What GI bleeding looks and feels like.

Vomited blood, black stool, fresh PR bleeding, anaemia and shock. The features below tell you when to act now.

  • Haematemesis

    Vomiting fresh red blood or coffee-ground material. A strong signal of active upper GI bleeding needing urgent assessment.

  • Melaena

    Black, tarry, offensive-smelling stool from partly digested blood. Usually upper GI, occasionally small bowel or right-sided.

  • Haematochezia

    Fresh red blood per rectum. Usually lower GI, but can be a massive upper GI bleed with rapid transit.

  • Blood mixed with stool

    Mixed with the stool, on the paper or dripping into the pan. Points to colorectal, diverticular or perianal sources.

  • Iron deficiency anaemia

    Occult blood loss over months. Fatigue, breathlessness and pallor. FIT and endoscopy find the source in most.

  • Shock and tachycardia

    Hypotension, tachycardia, pallor, cold peripheries or altered consciousness. A medical emergency needing resuscitation.

  • Chronic liver disease

    Jaundice, spider naevi, ascites, splenomegaly and caput medusae raise the pre-test probability of variceal bleeding.

  • Red flag - haemodynamic instability

    Systolic BP under 100, heart rate over 100, syncope or ongoing frank bleeding needs emergency department attendance now.

Treatment

How GI bleeding is treated in the UK.

Resuscitation, PPI or terlipressin, endoscopic haemostasis, band ligation, TIPS and IR embolisation. Surgery only as a last resort.

  • Resuscitation and transfusion

    ABC, wide-bore access, crystalloid then blood. Restrictive transfusion target of 7 to 8 g/dL per Villanueva. Reverse anticoagulation as guided by haematology.

  • Proton pump inhibitor

    IV omeprazole 80 mg bolus followed by 8 mg per hour infusion for high-risk ulcer bleeding, continued after endoscopic therapy.

  • Terlipressin and antibiotics

    Terlipressin and broad-spectrum antibiotics for suspected variceal bleeding, started before endoscopy where clinically indicated.

  • Endoscopic haemostasis

    Combination therapy with adrenaline injection, haemoclips, thermal coagulation or haemospray at gastroscopy for actively bleeding ulcers and Dieulafoy lesions.

  • Variceal band ligation

    Endoscopic band ligation at diagnostic gastroscopy is first-line for oesophageal varices. Repeat sessions until eradicated.

  • TIPS for refractory varices

    A transjugular intrahepatic portosystemic shunt reduces portal pressure when band ligation fails or as pre-emptive therapy in high-risk patients.

  • IR embolisation

    Selective mesenteric angiography and embolisation for ongoing bleeding when endoscopy fails or is not feasible, led by interventional radiology.

  • Surgery as a last resort

    Emergency surgery is reserved for uncontrolled bleeding despite endoscopy and interventional radiology, or where those options are unavailable.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, emergency team or gastroenterologist knows your history and can tell you which parts apply to you. If you are bleeding now, do not read on. Call 999.

  • NICE CG141. Acute upper gastrointestinal bleeding in over 16s: management.

  • British Society of Gastroenterology (BSG). Guidelines on the management of acute lower gastrointestinal bleeding.

  • BSG. UK guidelines on the management of variceal haemorrhage in cirrhotic patients.

  • Villanueva C et al. Transfusion strategies for acute upper gastrointestinal bleeding. NEJM.

Red flags

When GI bleeding needs urgent attention.

Most bleeds are managed in hospital. These are the situations where you should not delay, or where the risks of missing a diagnosis are highest.

  • Haemodynamic instability

    Shock, hypotension or tachycardia with ongoing bleeding is a medical emergency. Call 999 or attend the emergency department now.

  • Massive haematemesis

    Large-volume vomiting of fresh red blood needs immediate resuscitation, cross-match and endoscopy in a high-dependency setting.

  • Suspected variceal bleeding

    Known cirrhosis or chronic liver disease with GI bleeding needs terlipressin, antibiotics and endoscopy within 12 hours.

  • Anticoagulation and bleeding

    DOACs, warfarin, dual antiplatelets or heparin with GI bleeding needs urgent reversal decisions guided by haematology.

  • Melaena with syncope

    Passing out with black stool suggests significant blood loss. Do not drive. Attend the emergency department.

  • Persistent haematochezia

    Ongoing fresh rectal bleeding, particularly with anaemia, weight loss or a change in bowel habit, needs urgent colonoscopy.

  • Iron deficiency anaemia

    Unexplained iron deficiency in men or postmenopausal women is a two-week-wait referral for suspected GI cancer.

  • Weight loss and bleeding

    Any GI bleeding with unintentional weight loss, anorexia or a mass warrants urgent upper and lower endoscopy.

  • Aortic-enteric fistula

    Rare but lethal. Consider in anyone with a prior aortic graft and a herald bleed. Needs immediate vascular and CT input.

Living with it

A treatable condition, once the source is found.

Four things that make the biggest difference after a bleed: careful follow-up, a medication review, alcohol moderation and knowing exactly when to come back.

A quiet reminder

The first 72 hours after a bleed are the highest risk.

Stay reachable, take your PPI as prescribed and do not restart NSAIDs or anticoagulants without a plan agreed by your specialist.

  1. 01 Recovery

    Take the follow-up seriously

    Most rebleeds happen within 72 hours. Attend every outpatient appointment and complete your PPI or eradication course in full.

  2. 02 Medicines

    Review NSAIDs and anticoagulants

    Stop over-the-counter ibuprofen and aspirin unless your specialist advises otherwise. Anticoagulants should only be restarted after a formal review.

  3. 03 Alcohol

    Cut down or stop drinking

    Alcohol worsens gastritis, ulceration and variceal bleeding. If you have cirrhosis, stopping entirely improves survival.

  4. 04 Warning

    Know when to come back

    Fresh vomited blood, black tarry stool, dizziness or fainting means calling 999 or attending the emergency department. Do not wait.

Frequently asked

Everything we get asked about GI bleeding.

Quick answers on causes, endoscopy, PPI therapy and when interventional radiology or surgery is needed.

  • What is gastrointestinal bleeding?

    Bleeding anywhere from the mouth to the anus. It is divided into upper GI (proximal to the ligament of Treitz), lower GI and small bowel or obscure sources. Presentation ranges from occult iron deficiency anaemia to life-threatening haemorrhage.

  • What are the most common causes?

    For upper GI bleeding, peptic ulcer disease driven by Helicobacter pylori and NSAIDs is the most common cause, followed by oesophageal varices and Mallory-Weiss tears. For lower GI bleeding, diverticular disease, angiodysplasia, haemorrhoids and colorectal cancer are the leading causes.

  • What is the difference between melaena and haematochezia?

    Melaena is black, tarry, offensive-smelling stool from partly digested blood, almost always from an upper GI source. Haematochezia is fresh red blood per rectum, usually from a lower GI source, though a massive upper GI bleed with rapid transit can look the same.

  • How urgent is a GI bleed?

    Any active bleeding with dizziness, fainting, chest pain or shortness of breath needs 999 or emergency department attendance. Stable but ongoing bleeding still needs same-day assessment. Occult blood loss with iron deficiency needs urgent outpatient endoscopy.

  • What happens at endoscopy?

    A gastroscopy examines the oesophagus, stomach and duodenum, allowing biopsies and immediate haemostasis with adrenaline, clips, thermal therapy or band ligation. A colonoscopy examines the colon and terminal ileum, with similar therapeutic options for polyps, diverticular bleeding and angiodysplasia.

  • When is interventional radiology used?

    When endoscopy cannot control the bleeding, cannot find the source or is not feasible. A CT angiogram identifies the bleeding vessel, and the interventional radiologist can then selectively embolise it through a catheter in the groin, avoiding open surgery in most cases.

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