What is the characteristic of melena in terms of stool appearance?

Melena is characterized by dark, tarry, sticky stool, which typically results from the digestion of blood coming from the upper gastrointestinal tract, such as the stomach or small intestine. The dark color is due to the breakdown of hemoglobin in the blood, which alters its color as it passes through the intestines. The appearance is often described as resembling tar, reflecting the combination of prolonged contact with digestive enzymes and the presence of digested blood. This condition often indicates a significant bleeding issue that requires urgent medical evaluation. Understanding this characteristic is essential for recognizing potential gastrointestinal bleeding and knowing when to seek medical intervention.