Why Is My Dog's Poop Black?

Why Black Poop Is a Red Flag

Black, tarry dog poop — known medically as melena — is one of the most concerning stool colors. The dark color and sticky texture come from digested blood, which means bleeding is occurring somewhere in the upper gastrointestinal tract (stomach or small intestine).

Common Causes of Black Dog Poop

• Upper GI bleeding — stomach ulcers, tumors, or severe gastritis can cause blood to enter the digestive tract. By the time it passes, the blood is digested and appears black.
• NSAID toxicity — medications like ibuprofen, aspirin, or prescription NSAIDs can cause stomach ulcers in dogs.
• Blood-clotting disorders — conditions that prevent normal clotting can lead to internal bleeding.
• Ingested blood — a dog that has licked a wound or had a nosebleed may pass black stool.
• Iron supplements or Pepto-Bismol — these can turn stool black without indicating a health problem.
• Diet — very dark kibble, liver treats, or blood-meal-based foods can darken stool.

Black Poop vs Dark Brown Poop

Not all dark stool is cause for alarm. The key differences:

If you are unsure, place a small amount of the stool on a white paper towel. True melena will leave a reddish-black streak, while dark brown stool from diet will look brown when smeared.

Breeds at Higher Risk

While any dog can develop upper GI bleeding, certain breeds are more susceptible to the underlying causes:

• German Shepherds — prone to EPI and IBD, which can lead to GI bleeding.
• Boxers — higher rates of GI tumors and ulcerative colitis.
• Rottweilers — susceptible to parvovirus, which can cause bloody stool.
• English Bulldogs — chronic GI inflammation from food allergies.

What to Do If You Find Black Poop in Your Yard

1. Note the time and take a photo for your vet.
2. Check your dog's gum color — healthy gums are pink. Pale or white gums indicate blood loss.
3. Review anything your dog may have ingested in the last 24-48 hours.
4. Contact your veterinarian. If after-hours, call an emergency animal hospital.
5. Collect a sample in a sealed plastic bag for testing.

When to See a Vet

Seek veterinary care if:

• Black, tarry stool persists for more than one bowel movement.
• Your dog shows signs of weakness, lethargy, or pale gums.
• Black stool is accompanied by vomiting (especially vomit that looks like coffee grounds).
• You cannot explain the dark color through diet or medications.
• Your dog is a puppy, senior, or has known GI issues.