Upper GI Bleeding and Black Stool - Understanding Medical Emergencies

Upper gastrointestinal bleeding can cause black, tarry stool (melena) and represents a potentially life-threatening medical emergency requiring immediate evaluation and treatment. Understanding the signs helps ensure prompt medical care.

Understanding Upper GI Bleeding

Upper gastrointestinal bleeding occurs in the esophagus, stomach, or upper small intestine (duodenum). When blood from these areas reaches the colon, digestive enzymes and bacteria change it to a black, tarry consistency called melena.

How Upper GI Bleeding Causes Black Stool

Blood Transformation:

• Hemoglobin breakdown: Digestive enzymes break down blood
• Bacterial action: Gut bacteria further process blood
• Iron oxidation: Iron in blood oxidizes to create black color
• Transit time: Longer passage allows complete color change

Melena Characteristics:

• Black color: Deep black, not brown
• Tarry consistency: Sticky, tar-like texture
• Strong odor: Distinctive, unpleasant smell
• Shiny appearance: Glossy, reflective surface