Analysis of information sources in references of the Wikipedia article "흑색변" in Korean language version.
Iron supplements cause a grayish-black stool that should be distinguished from the black, tarlike stool that occurs from bleeding ulcer.
Melena strongly suggests, and hematemesis confirms, that bleeding is of upper gastrointestinal origin…Peptic ulcer, the most common cause of gastrointestinal hemorrhage, should be pursued through questions about epigastric distress, the relationship of symptoms to food intake, and a past history of peptic ulcer disease..
