Black or Tarry Stools UF Health Stool Colors and What They Can Tell You Your stool color can carry important clues about digestion, diet, or even disease. Most shades are harmless, but some changes signal the need for Hematochezia vs Melena: Symptoms, Causes, Diagnosis, Treatment Black, tarry stools are NOT normal. They could be a sign of Melena upper gastrointestinal bleeding that requires urgent medical attention. Learn the difference between Melena vs Hematochezia, common