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What Are the Causes of Black Dog Poop?

Is black dog poop ever normal or should you get your dog to the vet ASAP if you notice that your dog's poop is black? Let's look at the causes of black dog poop and what to do about it.

Jennifer Lesser  |  Aug 10th 2018


When it comes to your pet’s health, sometimes the proof is in the poop. Most pet parents will schedule a visit with the veterinarian if their pet’s droppings suddenly change size or consistency. But what about when your dog’s poop suddenly turns an unusual color, like black? Is black dog poop normal or a cause for concern?

Why Black Dog Poop Happens

A dog squatting or pooping and peeing in a grass field.

What might cause black dog poop? Photography © winyoo08 | iStock / Getty Images Plus.

“A normal stool for a dog should be firm and dark brown in color … and the color of the stool should be fairly consistent from day to day, providing the dog eats a regular diet,” explains Dr. Dawn M. Spangler, assistant professor of shelter medicine at Lincoln Memorial University College of Veterinary Medicine in Tennessee.

Though it’s a relatively rare occurrence, when the color of your pet’s poop suddenly takes on a black, tarry appearance, it can actually point to a number of digestive conditions. According to Dr. Ramon Nieves, owner of Del Mar Veterinary Hospital in Florida, that tarry black dog poop is known as melena, and is typically a result of digested blood in your dog’s poop. Though it’s not actually a condition itself, melena is a symptom of some other underlying health issue, such as a blood clotting disorder or an ulcer.

“A common complaint by pet owners is that they’ve spotted some blood in their pet’s stool, and as veterinarians we can pinpoint where the bleeding is occurring in the GI tract based upon the color they describe … whether it’s dark or bright red, or even black,” Dr. Nieves explains. He notes that black dog poop typically occurs as a result of bleeding in the upper portion of the gastrointestinal tract; the dark color and tarry consistency of the feces signifies the digestion of blood as it has passed through the intestinal tract. It may also occur if your dog has ingested a significant amount of blood from the respiratory tract — such as if he’s been coughing and swallowing blood from his lungs, or even if he’s had a nosebleed.

So, Why Is Black Dog Poop … Black?

Whatever the cause, black or tarry stools indicate that there is bleeding in the stomach or small intestine of the dog, Dr. Spangler confirms. “The stool is black because the blood has been digested, causing it to change color,” she says. The causes of melena vary widely, and can mean anything from exposure to toxins or a foreign body in the gastrointestinal system to pancreatitis and kidney failure. “A few of the more common causes of black dog poop are cancer, foreign bodies, parasites, and viral or bacterial pathogens,” Dr. Spangler adds.

What to Do About Black Dog Poop

That’s why if you notice black dog poop — or you suspect that your dog is experiencing any sort of gastrointestinal upset — call your veterinarian as soon as possible. Symptoms such as your dog refusing his food or water for more than 24 hours — or if he or she is experiencing persistent vomiting or diarrhea — are always a cause for concern, Dr. Spangler notes. “Dogs can quickly become dehydrated, so it’s better to see a veterinarian sooner rather than later to get them the care and treatment they need,” she adds.

Pet owners should also tune in to their dog’s overall behavior, such as if your normally perky pooch is suddenly spending the entire day on the sofa. “Another symptom to notice is if you pick up your pet and they whine or cry … dogs and cats get stomach cramps and pains just like we do when something isn’t right,” Nieves says.

If you’ve discovered that your pet’s droppings have turned from their usual brown to black, Spangler explains that your pet’s veterinarian may check your dog’s stool samples for intestinal parasites, assess abdominal x-rays, and run blood work to help determine the definitive cause of the black color in your dog’s poop. “Treatment will depend upon the diagnosis,” she says, “but could include things such as anti-parasitics, antibiotics, antacids or anti-nausea drugs.”

Tell us: Has your dog ever experienced black poop? What was causing that black dog poop?

Thumbnail: Photography © DieterMeyrl | iStock / Getty Images Plus.

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