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 What Causes Black or Tarry Stool? Melaena appearance, causes, mechanism, sign value What does your poop colour indicate? Pay attention. There's a lot to be learned by the colour and consistency of your stools, as well as the frequency and how easily passed