Gastrointestinal Bleeding

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What is Gastrointestinal Bleeding? 

It is important to understand that gastrointestinal (GI) bleeding is not a disease, but a symptom of a disorder in your digestive tract. It refers to the presence of blood in stool or vomit, and stools may look black or tarry. 

Extensive bleeding in the GI tract can be dangerous, but small amounts of bleeding can lead to several problems as well, such as anaemia or low blood counts. This makes it paramount to get to the root cause of the GI bleeding and to manage the condition effectively. 

What Causes Gastrointestinal Bleeding? 

There are many causes of GI bleeding, and it can occur in either the upper or lower GI tract.

Upper GI bleeding causes can include:

  • Peptic Ulcers — This is the most common cause of upper GI bleeding. Peptic ulcers are sores that develop along the stomach lining and the upper portion of the small intestine. Stomach acid, either from bacteria or the use of anti-inflammatory drugs, damages the lining, leading to the formation of sores.
  • Mallory-Weiss Tears — This condition refers to tears in the lining of the oesophagus, often caused by excessive alcohol consumption, violent coughing or vomiting. 
  • Oesophageal Varices (abnormal, enlarged veins in the oesophagus) — This condition occurs most often in people with advanced liver disease.
  • Oesophagitis — This inflammation of the oesophagus is most commonly caused by gastroesophageal reflux disease (GERD).

Lower GI bleeding causes can include:

  • Diverticular Disease — Development of small, bulging pouches in the digestive tract, also known as diverticulosis. If one or more of the pouches become inflamed or infected, it's called diverticulitis.
  • Inflammatory Bowel Disease (IBD) — This includes ulcerative colitis, which causes inflammation and sores in the colon and rectum, Crohn's disease, and inflammation of the lining of the digestive tract.
  • Tumours — Non-cancerous (benign) or cancerous tumours of the oesophagus, stomach, colon or rectum can weaken the lining of the digestive tract and cause bleeding.
  • Colon Polyps — Small clumps of cells that form on the lining of your colon can cause bleeding. Most are harmless, but some might be cancerous or can become cancerous if not removed.
  • Haemorrhoids — These are swollen veins in your anus or lower rectum, similar to varicose veins.
  • Anal Fissures — These are small tears in the lining of the anus.
  • Proctitis — Inflammation of the lining of the rectum, causing rectal bleeding.

What are signs that you have Gastrointestinal Bleeding?

Signs and symptoms of GI bleeding can be either obvious (overt) or hidden (occult). Depending on the location and the rate of the bleeding, signs and symptoms can be anywhere on the GI tract, from the mouth to the anus.

Obvious (overt) bleeding might show up as:

  • Vomiting blood, which might be red or might be dark brown and resemble coffee grounds in texture
  • Black, tarry stool
  • Rectal bleeding, usually in or with stool

With hidden (occult) bleeding, you might have:

  • Lightheadedness
  • Difficulty in breathing/shortness of breath
  • Fainting
  • Chest pain
  • Abdominal pain
  • Symptoms of shock

If your bleeding starts abruptly and progresses rapidly, you could go into shock. Signs and symptoms of shock include:

  • Drop in blood pressure
  • Not urinating or infrequently urinating in small amounts
  • Rapid pulse
  • Unconsciousness

Can you bleed internally without knowing it?

Yes, you can. This is known as hidden or occult gastrointestinal bleeding. 

Is Gastrointestinal Bleeding painful?

Depending on where the bleeding is, GI bleeding can either feel pain or not at all.

Is Gastrointestinal Bleeding life-threatening?

Depending on the severity of bleeding, GI can be considered mild to severe or even life-threatening.

When should I see a doctor?

If you have symptoms of shock, you or someone else should call your local emergency medical number. If you're vomiting blood, see blood in your stools or have black, tarry stools, seek immediate medical care. For other types of GI bleeding, make an appointment with your doctor.

How is Gastrointestinal Bleeding Diagnosed?

Diagnosis of the underlying cause of your GI bleeding will usually start with a doctor asking about your symptoms and medical history. The doctor may also request a stool sample to check for the presence of blood, along with other tests to check for signs of anaemia.

Diagnosing GI bleeding

To diagnose GI bleeding and figure out what’s causing it, a doctor may perform the following tests:

  • Gastroscopy — Upper GI bleeding is most commonly diagnosed with an endoscopy. This procedure involves the use of a small camera located atop a long, flexible endoscopic tube the doctor places down your throat. The scope is then passed through your upper GI tract. The camera allows the doctor to see inside your GI tract and potentially locate the source of your bleeding.
  • Enteroscopy — This procedure is performed if the cause of your bleeding isn’t found during an endoscopy. An enteroscopy is similar to an endoscopy, except there’s usually a balloon attached to the camera-tipped tube. When inflated, this balloon allows your doctor to open up the small intestine and see inside.
  • Colonoscopy — During a colonoscopy, your doctor will insert a small, flexible tube into your rectum. A camera is attached to the tube so your doctor can view the entire length of your colon. Air moves through the tube to provide a better view.
  • Biopsy —During the colonoscopy, the doctor may take a biopsy for additional testing.
  • Radionuclide scan — You may also undergo a scan to locate your GI bleeding. A harmless radioactive tracer will be injected into your veins. The tracer will light up on an X-ray so your doctor can see where you’re bleeding.
  • CT Angiography — A CT scan is an imaging test that can help the doctor locate GI bleeding in the abdomen and pelvis. It often shows more detail than an X-ray.
  • Capsule Endoscopy — If your doctor can’t find the source of your bleeding with an endoscopy or a GI bleeding scan, they may perform a capsule endoscopy. Your doctor will have you swallow a pill that contains a small camera that will take pictures of your bowel to find the source of your bleeding.

How is Gastrointestinal Bleeding Treated?

  • Medicine — When infections or ulcers cause bleeding in your GI tract, healthcare professionals prescribe medicines to treat the problem.
  • Surgery — When a person has severe acute bleeding or bleeding that does not stop, a surgeon may need to perform a laparoscopy or a laparotomy to stop the bleeding.

Can I leave Gastrointestinal Bleeding untreated?

Complications might occur, such as:

  • Shock
  • Anaemia (low haemoglobin)
  • Death

How can I prevent or reduce Gastrointestinal Bleeding?

To help prevent a GI bleed:

  • Limit your use of nonsteroidal anti-inflammatory drugs.
  • Limit your use of alcohol.
  • Quit smoking
  • Manage GERD symptoms, if any.


Gastrointestinal Bleeding can range from mild to severe and even be life-threatening. This article aims to provide insights into GI bleeding and what symptoms or signs to look out for. Do consult your doctor or visit your doctor regularly and conduct checkups. Do alert your Gastroenterologist, especially in cases of obvious bleeding.


  1. “GI Bleed | Gastrointestinal Bleeding.” MedlinePlus, 4 May 2016, Accessed 28 November 2022.
  2. “Mallory-Weiss Tear.” Johns Hopkins Medicine, Accessed 28 November 2022.

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Dr Benjamin Yip

Consultant Gastroenterologist
MBBS (Singapore), MRCP (UK), MCI (NUS), FRCP (Edin), FASGE (USA), FAMS (Gastroenterology)

Dr Benjamin Yip is a Consultant Gastroenterologist and the Medical Director of the Alpha Digestive & Liver Centre.

Dr Yip believes that gastrointestinal health is hugely interconnected to our whole-body health and sees patients with General Medical, as well as Gastroenterology and Hepatology problems.

His expertise lies in Advanced Endoscopy, including complex endoscopic procedures such as ERCP, EUS, single balloon enteroscopy, Spyglass cholangioscopy and enteral dilation/stenting.

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