Why is my poop green? Stool colors explained 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 Black stool? Bright red blood? Each tells a different story. I've explained what these signs indicate and when to seek help. Watch the video, and if you relate to any of these Black Stool: A Warning Sign for Your Health?