Purple Stool: Benign Dietary Causes vs. GI Bleeding Emergency

Normal stool is brown. Purple feces suggest:

• Dietary (harmless): Large amounts of beets, blueberries, blackberries, purple grapes, red dye (e.g., sports drinks, frosting).
• Medications: Bismuth subsalicylate (Pepto-Bismol) → black/purple; iron supplements → dark green/black.
• Pathologic (urgent): Upper GI bleed (melena = tarry black, but brisk bleed + rapid transit → maroon/purple); colonic neoplasm, angiodysplasia, diverticular bleed.

Action: If purple stool + abdominal pain, nausea, vomiting, lightheadedness, or known anticoagulant use → emergency evaluation. Otherwise, review recent diet/meds; if unexplained, see clinician.