Passing black stool may be an indication of a variety of issues including inflammation, trauma and malignancy. Black stool with tarry texture is usually an indication of bleeding from the upper gastrointestinal tract. Red stool may be an indication of bleeding in the lower gastrointestinal tract, notes Health Grades.
The color of stool an individual passes may act as an indicator of various conditions. Black stool is normally a result of bleeding in the stomach, esophagus or small intestine. Left untreated, this condition may lead to serious complications including anemia, extreme blood loss or hemorrhage, shock and spread of cancer.
Taking certain medications and foods have also been known to cause black stools. Examples of substances that may lead to this condition include black licorice, iron supplements and Pepto-Bismol. Patient history, lab tests and physical examination are some of the methods doctors may use to diagnose this condition.
Another common stool color is green, which indicates that food is moving too fast through the digestive system. Yellow, greasy, foul-smelling stool may indicate excessive fat in the stool due to a disorder or malabsorption. In most cases, stool color depends on diet. Brown- and green-colored stool is generally considered normal, according to Mayo Clinic.