Cat Poop Black And Tarry: Why It Is A Medical Emergency (Melena Explained)

The litter box is your cat's health report card. Most days, it is boring. But sometimes, it delivers a terrifying message.

If you are scooping the box and find stool that is jet black, shiny, and sticky like road tar, this is not just "a weird poop."

This is Melena.

It indicates that your cat is bleeding internally in their stomach or upper intestines. Unlike bright red blood (which usually means a minor rectal tear), black blood has been digested. This is a medical emergency that requires immediate veterinary attention.

1. What Is Melena? (The Chemistry)

Why is the blood black?

When a cat bleeds in the upper gastrointestinal tract (stomach or small intestine), the blood mixes with stomach acid and digestive enzymes. As it travels down the system, the red hemoglobin is oxidized and digested, turning it a dark, tarry black color.

WARNING: Melena usually has a distinct, foul smell. It smells "metallic" (like old pennies) or rotting, much worse than normal poop.

2. The Texture Test: Constipation vs. Melena

Not all black poop is dangerous. You must check the consistency.

Scenario A: Black & Hard (Dry Pebbles) If the stool is very dark brown or black but comes out in hard, dry, individual pellets, this is usually Constipation.

• Cause: Dehydration or a diet too high in bone content.
• Risk Level: Moderate. Your cat needs water and fiber, but they are likely not bleeding.

Scenario B: Black & Tarry (Sticky Paste) This is Melena. It looks like unformed glistening asphalt or blackberry jam. It sticks to the litter scoop and smears easily.

• Cause: Internal Bleeding.
• Risk Level: Critical.

3. Top 3 Silent Killers (Causes)

Why would a house cat suddenly start bleeding internally?

1. Toxin Ingestion (Rat Poison)

This is a common cause. Rodenticides work by stopping blood from clotting. If your cat eats a poisoned mouse (or the bait itself), they will bleed internally.

• Signs: Melena, nosebleeds, bruising on the skin.

2. NSAID Toxicity (Human Meds)

Did your cat accidentally eat a Tylenol or Ibuprofen dropped on the floor? Or did you try to treat their pain with human medicine?

• The Damage: NSAIDs strip away the protective lining of a cat's stomach, causing severe gastric ulcers that bleed heavily.

3. Foreign Bodies

Cats love string and bones. If a sharp chicken bone or a linear object (like a sewing needle) moves through the gut, it can slice the intestinal wall, causing slow, continuous bleeding.

4. The "Checklist" Before You Go

You need to act fast, but gathering data helps the vet save your cat.

1. Check the Gums: Lift your cat's lip.
   • Pink: Good circulation.
   • Pale/White: Severe anemia (blood loss). This means they are in shock.
2. Take a Photo: Don't just describe it. Take a clear photo of the stool with flash.
3. Collect a Sample: If possible, put the sample in a ziplock bag. The vet can test it for "occult blood" instantly.

5. Are There False Alarms?

Yes, a few harmless things can cause black stool.

• Iron Supplements: If your cat is already being treated for anemia, iron pills turn poop black.
• Activated Charcoal: If they were treated for poisoning recently, the charcoal will dye the stool black.
• Bloody Meat: A raw diet rich in organs (spleen/liver) can sometimes darken the stool, but it rarely makes it "tarry."

Final Thoughts

Can wet food cause black poop in cats?

Generally, no. Wet food might make the stool softer or darker brown, but it should not turn it black and tarry. The only food-related exception is a raw diet rich in blood organs like spleen.

Does stress change cat poop color?

Stress usually causes diarrhea or mucus in the stool (colitis), but it rarely changes the color to black. Black almost always indicates blood or iron/charcoal ingestion.

How to collect a stool sample for the vet?

Turn a ziplock bag inside out over your hand. Grab a fresh sample (ideally within 4 hours). Invert the bag and seal it. Keep it in a cool place (double bagged) until your appointment.

If you see black, tarry stool, do not post on Facebook asking for advice. Do not wait to see if they eat dinner. Also check the other end: see our cat vomit color guide for more diagnostics.

Internal bleeding is a ticking clock. It is one of the most critical sick cat symptoms you can find. The black stool you see now represents blood lost 12-24 hours ago. Your cat may be more critical than they look.