Tarry, black, malodorous stook

• In most cases, the source is proximal to the ligament of Treitz but can occur as far down as the proximal colon.

DDx

• Often indicate UGIB - Upper GI Bleed → the blood has been exposed to the digestive process and intestinal bacterial fermentation
• Certain medications can cause the stools to look dark in colour, although they change the colour only and not consistency (i.e. not tarry).
  • Iron Supplement
  • Bismuth
• Poor lighting