Dark Blood in Cat Poop: What It Means
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Dark blood in cat poop appears as black, tarry, or very dark red stool.
Updated: 2026-07-31
Quick Answer
Dark blood in cat poop (melena) typically indicates digested blood from the upper gastrointestinal tract, which can result from stomach ulcers, intestinal bleeding, or certain medications. Dark tarry stool is different from bright red blood and should be treated as potentially serious. Contact a veterinarian promptly, especially if accompanied by weakness, vomiting, or appetite loss.
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What This May Mean
Dark blood in cat poop appears as black, tarry, or very dark red stool. This typically indicates digested blood (melena) from the upper gastrointestinal tract, such as the stomach or small intestine. The blood turns dark as it is digested during passage through the digestive tract. Dark, tarry stool should be treated as potentially serious.
Cats are obligate carnivores, and their stool reflects diet, hydration, and digestive health. Because most cats use litter boxes, owners have a regular opportunity to observe stool color, consistency, and frequency. Changes in litter box habits or stool appearance can sometimes be the first sign of a health issue, which is why paying attention to what is normal for your cat is important.
Possible Causes
Several factors may contribute to this stool appearance in cats. A veterinarian can help determine which are relevant for your cat.
- Digested blood from upper gastrointestinal bleeding, which turns stool black and tarry
- Stomach ulcers or inflammation that causes slow, persistent bleeding
- Ingestion of blood from grooming wounds or oral and nasal bleeding
- Certain medications, including some anti-inflammatory drugs, that irritate the stomach lining
- Intestinal conditions such as foreign bodies, tumors, or inflammatory disease
Keep in mind that stool changes can result from more than one factor at the same time. A veterinarian can perform a physical exam, fecal testing, blood work, or imaging to narrow down the cause. Avoid making assumptions based on appearance alone, since different conditions can produce similar stool changes.
Home Observation
When monitoring this change at home, the following details can help you and your veterinarian assess the situation:
Note whether the stool is truly black and tarry or dark red, and whether it has a strong, unusual odor. Check for weakness, pale gums, vomiting (especially coffee-ground material), appetite loss, or collapse. Take a photo and record the date and any recent medication or dietary changes.
Litter Box Monitoring Tips
- Scoop the litter box at least once daily so you can notice changes promptly
- Note the number of stool clumps, their size, color, and consistency each day
- Take a clear photo of unusual stool so you can show your veterinarian
- Track whether your cat is spending more or less time in the litter box than usual
- Keep a simple log of dates, dietary changes, and any other symptoms
When to Contact a Veterinarian
Dark, tarry stool should be treated as potentially serious. Contact a veterinarian promptly if you notice melena, especially if accompanied by weakness, pale gums, vomiting blood or coffee-ground material, appetite loss, collapse, or abdominal pain. Do not wait if these signs are present.
Signs that warrant urgent veterinary attention include:
- Large amounts of blood in the stool or dark, tarry stool
- Repeated vomiting, especially with blood or coffee-ground material
- Severe lethargy, collapse, or weakness
- Pale gums or signs of dehydration (sunken eyes, dry gums, skin tenting)
- Abdominal pain, swelling, or distress
- No stool production for more than two days with straining
Kittens, senior cats, and cats with existing medical conditions are at higher risk of complications and should be evaluated promptly.
If you are unsure whether the situation is urgent, calling a veterinary clinic for guidance is a reasonable step. Many clinics can advise you over the phone on whether your cat should be seen immediately or can wait for a scheduled appointment. Having a photo of the stool and a record of when changes started can help the veterinary team triage the situation.
Frequently Asked Questions
What does dark, tarry cat poop mean?
Dark, tarry stool (melena) typically indicates digested blood from the upper gastrointestinal tract, such as the stomach or small intestine. This can result from ulcers, bleeding disorders, or other conditions. Contact a veterinarian promptly for evaluation.
Is dark blood in cat poop more serious than bright red blood?
Dark, tarry blood (melena) and bright red blood (hematochezia) both warrant veterinary attention, but melena may indicate upper gastrointestinal bleeding, which can be more serious. Both should be evaluated promptly, especially if accompanied by weakness, vomiting, or appetite loss.
POOP SCANNER
Describe what you see and get a prioritized, evidence-based assessment of possible causes.
This tool provides general information and does not replace a veterinarian's diagnosis.
Sources
- Cornell Feline Health Center, Cornell University College of Veterinary Medicine
- VCA Hospitals, Veterinary Clinical Articles
- Merck Veterinary Manual, Merck & Co., Inc.
Disclaimer
This article and the PawAI Poop Scanner tool provide general information and do not replace examination, diagnosis, or treatment by a licensed veterinarian. If your cat shows concerning signs, contact a veterinarian.