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Clinical Symptom🐕 Dogs🐈 Catsgastrointestinalhematologic immune

Melena

🗣️ Pronounced:meh-LEE-nuh
In One Sentence (Plain English)

The passage of dark, black, sticky, tar-like feces containing digested blood originating from the upper gastrointestinal tract.

Editorial Status: Verified from peer-reviewed veterinary sources (v1.0)
Updated: 2026-01-15

💬 In Plain English

Melena describes stool that is pitch-black, shiny, and sticky like road tar, with a uniquely foul, metallic odor. This black color occurs because blood from the stomach or upper small intestine has been exposed to stomach acid and digestive enzymes, which oxidize and digest the hemoglobin into a dark pigment called hematin. Unlike hematochezia (which is fresh bright red blood from the lower colon), melena indicates substantial bleeding higher up in the digestive tract, such as a bleeding stomach ulcer, swallowed blood from the airway, or a bleeding tumor.

🔬 Clinical & Technical Depth

For Vets & Technicians

Formal Clinical Definition

Evacuation of dark, pitch-black, tarry stools containing digested blood hemoglobin (converted to acid hematin). Typically indicates bleeding of at least 50–100 mL within the upper gastrointestinal tract (oral cavity, pharynx, esophagus, stomach, or proximal small intestine).

Why Veterinarians Use It

Veterinarians treat melena as an urgent indicator of severe upper GI hemorrhage, most commonly triggered by NSAID-induced gastric ulceration or gastrointestinal tumors.

Clinical Context Encountered

Seen in dogs given human NSAIDs (like ibuprofen or aspirin), pets receiving concurrent steroids and NSAIDs, or dogs with bleeding mast cell tumors or intestinal carcinomas.

Clinical Reference Guide (Clinical Symptom)

Urgency Level

🚨 Red Flag Warnings (When to Contact an Emergency Vet)
  • •Melena represents significant internal blood loss. Never give NSAIDs and corticosteroids together, and NEVER give human ibuprofen, naproxen, or aspirin to pets.

❓ Questions to Ask Your Veterinarian

Take these actionable questions with you to your next clinic visit or appointment:

  • 1Has my pet received any NSAIDs (like carprofen or human ibuprofen) or corticosteroids (like prednisone)?
  • 2What is my pet’s packed cell volume (PCV) to check for significant blood loss anemia?
  • 3Does my pet need gastroprotectants like sucralfate (Carafate) and proton pump inhibitors (omeprazole)?
  • 4Could a bleeding stomach ulcer, mast cell tumor, or intestinal mass be present?

Academic & Clinical References