What is Gastrointestinal Bleeding?


Gastrointestinal bleeding (GIB) is characterized by the loss of blood in the gastrointestinal (GI) system, also called the digestive tract.

The GI system consists of the; 

  • Mouth
  • Pharynx
  • Esophagus
  • Stomach
  • Small intestine
  • Large intestine
  • Anus

Blood loss can occur in any part of the system.1,2 The haemorrhage or bleeding can differ among patients. It can be acute, mild, chronic or even life-threatening. Therefore, it is important to know the causes of GIB and how to treat and prevent it. 

Types of gastrointestinal bleeding

GIB can be classified into different types based on the severity and location of the hemorrhage:3

  • Upper GIB: This type of bleeding occurs in the upper part of the GI tract including the esophagus, stomach and the first part of the small intestine (called the duodenum).
  • Lower GIB: This kind occurs in the lower part of the GI tract including the colon, rectum and anus. 
  • Obscure GIB or Small Bowel bleeds: In this type, bleeding occurs in the middle part of the GI tract including the jejunum and ileum which are the middle and last part of the small intestine respectively. 

Causes of gastrointestinal bleeding

GIB usually occurs either in the upper or lower GI tract and it can happen due to various reasons. Causes of GIB in the upper GI tract include:2,3,4,5,6

  • Peptic ulcers which can occur due to infection with helicobacter pylori or excessive use of nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Tear in a vein in the esophagus
  • Tear in the walls of the esophagus which is known as Mallory-Weiss syndrome caused by excessive vomiting 
  • Ingestion of foreign body which can cause tears in the GI and bleeding
  • Gastritis and duodenitis both of which are usually caused by H. pylori infection or overuse of NSAIDs or alcohol
  • Esophagitis which is an inflammation in the esophagus caused by gastroesophageal reflux disease (GERD)
  • Tumors in the upper GI including esophageal cancer, stomach cancer or small intestine cancer that can cause bleeding
  • Angiodysplasia which is the enlargement of blood vessels

Causes of GIB in the lower GI tract include:2,3,4,5,6

  • Hemorrhoids which are enlarged veins in the rectum that cause bleeding 
  • Diverticulosis which happens when the wall of the colon pushes against vessels, causing them to rupture
  • Colon cancer
  • Anal fissure which is a tear in the anal sphincter
  • Angiodysplasia
  • Colitis or the inflammation of the colon
  • Inflammatory bowel disease which might happen due to nflammation in the colon and rectum, Crohn’s disease or inflammation of GI tract lining
  • Tumors 
  • Colon polyps which are clumps of cells on the colon lining that cause bleeding 
  • Proctitis which is the inflammation in the lining of the rectum

Signs and symptoms of gastrointestinal bleeding

Signs and symptoms may be hidden or obvious and also depend on the location of the bleeding.

Signs and symptoms of GIB include:2,3,5,6,7

  • Dark stool
  • Blood in vomit
  • Abdominal cramps
  • Chest pain
  • Blood in stool
  • Dizziness
  • Faintness
  • Tiredness
  • Weakness
  • Paleness
  • Shortness of breath
  • Anemia
  • Inflammation
  • Cancer 

Excessive bleeding can cause a systemic shock. Symptoms of shock include:

  • Dropped blood pressure
  • Limited urination
  • Unconsciousness
  • Rapid pulse

Management and treatment for gastrointestinal bleeding

Treatment of GIB may depend on the source of the bleeding. Sometimes the bleeding may stop without any treatment. However, in many cases where it does not stop, depending on the location, a procedure or medication may be necessary to control it. In some cases, where bleeding is caused by haemorrhoids or ulcers, the doctor may prescribe medications for reducing stomach acid, helping the blood to clot and relieve swelling.3 During the diagnostic tests (upper/lower GI endoscopy, colonoscopy, flexible sigmoidoscopy) that the doctor will carry out to discover the source of the bleeding, they can stop the bleeding through various ways:2

  • Injecting medicine into the site of the bleeding
  • Placing a band or a clip to the affected blood vessels
  • Using heat probes, lasers or electric currents to treat the tissue

If the bleeding is unstoppable or acute, the doctor may have to perform a laparotomy/laparoscopy.2

Diagnosis of gastrointestinal bleeding

When visiting a doctor, they will take a medical history and they will conduct a physical exam that includes listening to the abdomen and tapping on different areas of it. Finally, depending on the symptoms, they will probably do some diagnostic tests in order to be able to give a full diagnosis. The tests include:2,3,5

  • Stool test
  • Blood test
  • Gastric lavage: a tube is entered through the nose all the way to the stomach to determine source of bleeding
  • Upper GI endoscopy: a tiny camera is placed at the end of a tube and enters through the mouth to examine the upper GI tract (esophagus and stomach)
  • Enteroscopy: this is done to examine the small intestine with a longer camera
  • Capsule endoscopy: in this procedure, a capsule is swallowed with a camera inside to examine the GI tract
  • Colonoscopy: a long tube containing a tiny camera is entered through the rectum to examine the lower GI tract (rectum and colon)
  • Flexible sigmoidoscopy: a tube with a small camera is used to examine the rectum and sigmoid colon
  • Balloon-assisted enteroscopy: it is used to examine parts of the small intestine that other tests cannot reach 
  • Angiography: a dye is inserted inside the artery and then X-ray imaging will reveal which vessels are bleeding
  • CT scan

Risk factors

GIB can happen to anyone and particularly those who suffer from other digestive problems such as peptic ulcers.

There are several risk factors however that you should keep in mind:6

  • Anticoagulants (drugs that thin the blood and might cause bleeding)
  • Excessive vomiting
  • Alcohol abuse
  • Recent surgery
  • Excessive NSAIDs use 
  • Old age
  • Persistent bleeding
  • Significant blood loss
  • Smoking 


Gastrointestinal bleeding can have life threatening effects. If left untreated, it can cause serious complications such as:4,5,6,8

  • Anemia
  • Shock
  • Cancer
  • Respiratory distress
  • Infection
  • Heart attack
  • Death


How common is gastrointestinal bleeding?

GIB is a relatively common medical condition affecting all ages. GIB prevalence varies depending on the cause. However, it is estimated that approximately 300,000 hospitalizations occur every year in the United States.9 In the UK, the mortality rate is high for people who have been hospitalized for GIB or developed GIB while hospitalized.10 There is an annual estimate of 70,000 hospitalizations in the UK due to GIB.11

How can I prevent gastrointestinal bleeding?

Below are some steps you can follow to prevent yourself from GIB:3

  • Quit smoking tobacco
  • Regular infection checks (for example helicopter pylori)
  • Get treatment to manage the symptoms 
  • Limit alcohol consumption
  • Take NSAIDs only when necessary
  • Avoid medications that can cause bleeding
  • Reduce stress
  • Adapt or maintain a healthy lifestyle
  • Balance your diet

When should I see a doctor?

If you notice any signs or symptoms of GIB, you should seek medical help immediately. You should call the emergency services if you have a fever, are confused or have a rapid heart rate. Other symptoms to watch for include seeing blood in the stools or dark stools, bleeding in the mouth or rectum or vomiting blood.6,8


Gastrointestinal bleeding is a severe medical condition where loss of blood in the digestive system occurs. It can be caused by several factors including ulcers, inflammation, medications and cancer. The core symptoms are dark stools, vomiting blood and abdominal pain. Diagnosis of GIB involves a variety of tests carried out by a doctor such as endoscopy, colonoscopy, CT scans, stool and blood tests. Treatment of this condition depends on the location of the bleeding and the severity. There are things you can do to prevent GIB such as maintaining a healthy lifestyle and diet, avoiding risk factors, and getting regular checks to manage other medical problems. It is fundamental to seek medical attention early if you show any signs of GIB in order to get the appropriate treatment and prevent further damage. 


  1. National Cancer Institute. 2023. Gastrointestinal Tract. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/gastrointestinal-tract
  2. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). 2023. Gastrointestinal (GI) Bleeding. https://www.niddk.nih.gov/health-information/digestive-diseases/gastrointestinal-bleeding/definition-facts
  3. Cleveland Clinic. 2023. Gastrointestinal (GI) Bleeding. https://my.clevelandclinic.org/health/diseases/23391-gastrointestinal-gi-bleeding
  4. Healthline. 2023. Everything you need to know about Gastrointestinal Bleeding. https://www.healthline.com/health/gastrointestinal-bleeding
  5. Mayo Clinic. 2023. Gastrointestinal bleeding. https://www.mayoclinic.org/diseases-conditions/gastrointestinal-bleeding/symptoms-causes/syc-20372729
  6. Medical News Today. 2023. What are the symptoms of gastrointestinal bleeding? https://www.medicalnewstoday.com/articles/gastrointestinal-bleeding
  7. MedlinePlus. 2023. Gastrointestinal Bleeding. https://medlineplus.gov/gastrointestinalbleeding.html
  8. National Health Service (NHS). 2023. Stomach ulcer. https://www.nhs.uk/conditions/stomach-ulcer/complications/
  9. Laine L, Yang H, Chang SC, Datto C. Trends for incidence of hospitalization and death due to GI complications in the United States from 2001 to 2009. Am J Gastroenterol; 2012. 107(8): 1190-1195. 
  10. Oakland K, Chadwick G, East JE, Guy R, Humphires A, Jairath V, McPherson S, Metzner M, Morris AJ, Murphy MF, Tham T, Uberoi R, Veitch AM, Wheeler J, Regan C, Hoare J. Diagnosis and management of acute lower gastrointstinal bleeding: guidelines from the British Society of Gastroenterology. Gut; 2019. 68: 776-789.
  11. Medscape. 2023. Upper Gastrointestinal Bleeding (UGIB). https://emedicine.medscape.com/article/187857-overview#a5
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Research Assistant at Imperial College London, Department of Brain Sciences

My name is Athina Servi, and I am a young professional with a strong academic background
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