Upper Gastrointestinal Bleeding: What Does Stool Look Like?

When it comes to upper gastrointestinal bleeding, one of the most common signs is the appearance of black, tarry stools. This type of stool, often referred to as melena, resembles asphalt or shiny shoe polish in both texture and color. It occurs when blood from the upper digestive tract, such as the stomach or the first part of the small intestine, is broken down by digestive enzymes, resulting in this distinctive dark appearance.

Understanding the Different Types of Stool in GI Bleeding

In some cases, particularly when the bleeding is rapid or occurs in large volumes, the blood may pass through the digestive system too quickly to be fully broken down. In these situations, the stool may appear as dark red or maroon-colored blood, rather than the typical black tarry appearance. This can sometimes be mistaken for lower gastrointestinal bleeding, so it's important to seek medical evaluation for accurate diagnosis.

Common Misconceptions About Black Stool

Many people confuse black stools with gastrointestinal bleeding when the dark color may actually be caused by certain foods or medications. For example, consuming animal blood (like pig's blood) or organ meats (such as liver) can temporarily darken the stool. Similarly, iron supplements and certain medications like bismuth subsalicylate can also cause black stools without any underlying bleeding.

How to Confirm Gastrointestinal Bleeding

If there is any concern about potential gastrointestinal bleeding, a fecal occult blood test (FOBT) should be performed at a medical facility. This simple test detects the presence of blood in the stool that may not be visible to the naked eye. A positive result indicates bleeding somewhere in the digestive tract, while a negative result suggests the dark stool is likely due to dietary or medicinal causes rather than internal bleeding.