Decisions: A 20 year old male with dark stool Department of Emergency Medicine Saint John Healthy Poop Chart: Is Your Poop Normal? Nikki Yelton RD What is the cause of recurrent melena stool with multiple telangiectasia and prominent veins in the proximal ascending colon in a 14 year old boy? Melena Stool Definition, Causes and More: Understand melena stool, dark and tarry stool often indicating upper gastrointestinal bleeding. Learn about potential causes and implications.: Arpilor, Mr. Leonardimer: 9798859376544: Amazon.com: Books Black or Tarry Stools UF Health 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.