TL;DR: Black, tarry stools (melena) indicate serious internal bleeding in your cat's upper gastrointestinal tract and require immediate emergency veterinary evaluation.
What does it mean if my cat has black or tarry stools?
Black, tarry, or sticky stools are medically known as melena. This specific appearance occurs when blood has been digested in the upper gastrointestinal tract, such as the stomach or small intestine. Unlike bright red blood (hematochezia), which indicates a problem in the colon or rectum, the dark color of melena suggests that internal bleeding has been chemically altered by stomach acids and digestive enzymes.
Should I take my cat to the emergency vet for black, tarry stools?
- Urgency Level: High
- Black tarry stools are a critical veterinary emergency.
- Melena is often a sign of significant internal bleeding caused by serious conditions such as stomach ulcers, ingestion of toxins (like rat poison), foreign body obstructions, or organ failure.
- Seek immediate emergency veterinary care if your cat also shows signs of lethargy, pale gums, or vomiting.
How does taking a photo of my cat's stool help the veterinarian?
- Taking a clear photo of your cat's stool provides an invaluable visual record for the veterinary team.
- A photo allows the vet to confirm the presence of melena versus dark-colored food.
- It helps the medical team assess stool consistency and gauge the severity of blood loss before you arrive.
- This information helps the clinic prioritize your cat's care and prepare necessary diagnostic equipment in advance.
Clinical Context (Merck Veterinary Manual)
Black, tarry feces (melena) in cats indicate hemorrhage in the stomach or small intestine. Specific clinical signs of gastrointestinal ulceration in cats include melena and, less commonly, hematemesis or hematochezia; however, affected cats frequently show only nonspecific signs such as anorexia and abdominal pain. While gastrointestinal ulceration is uncommon in cats, it can be associated with neoplasia (e.g., lymphoma, adenocarcinoma) or may be of unknown cause.
Chapter: Gastroenterology, Infectious Disease
Source: The Merck Veterinary Manual, 11th Edition (Page 156)