Melaena Causes Diagnoses Management TeachMeSurgery Black Stool: A Warning Sign for Your Health? Melaena Causes Diagnoses Management TeachMeSurgery Dark stool vs black stool the difference can be serious. Dark brown stool is often food or iron related. Black, tarry stool may indicate internal bleeding and needs urgent medical attention. Foods That Cause Dark Stools and When to Be Concerned GoodRx Types of Poop: What Doctors Need You to Know The Healthy @Reader's Digest