Gastrointestinal bleeding can take many forms. It can be:

• Acute – manifesting with a severe, life-threatening emergency.
• Chronic – slow bleeding that may not even be visible to the naked eye, and presenting with iron deficiency anaemia (See Anaemia).
• Upper gastrointestinal tract – originating from the oesophagus, stomach or duodenum usually.
• Lower gastrointestinal tract – usually the colon or rectum, but sometimes originating from the small bowel distal to the duodenum.

As such, the symptoms of gastrointestinal tract bleeding are widely varied. Vomiting blood (haematemesis), blood in the stools (haematochezia) or black, sticky stools (melena) are all manifestations of GI bleeding. GI bleeding may even be present but not apparent without appropriate testing.

Acute bleeding is caused by upper GI tract pathology more frequently than lower GI tract pathology. Examples of causes of both are given below.

Upper gastro-intestinal tract bleeding:

• Peptic ulcer disease and gastritis
• Oesophageal varices
• Gastric cancer
• Vascular abnormalities

Lower gastro-intestinal tract bleeding:

• Colorectal cancer
• Inflammatory bowel disease
• Diverticulosis
• Vascular abnormalities

In gastrointestinal tract bleeding, a cause should always be sought. This will usually include endoscopy (gastroscopy and/or colonoscopy).