Black, Tarry Feces due to Presence of Blood in Dogs

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The term melena is used to describe black, tarry stools in dogs, which is due to the presence of digested blood in the feces.

Melena in dogs typically occurs due to bleeding in the upper portion of the gastrointestinal tract. It has also been seen after they have ingested a sufficient amount of blood from the respiratory tract—for example, from a nosebleed or from coughing up and swallowing blood from the lungs.

Dog melena is not a disease in itself but a symptom of an underlying condition such as a gastrointestinal ulcer or blood clotting disorder. The dark color and tarry consistency of the feces occurs because the blood is digested as it passes through the intestinal tract.

Symptoms and Types of Melena in Dogs

Other symptoms related to melena in dogs depend on the bleeding’s underlying cause, severity and location.

  • In patients with gastrointestinal bleeding, other symptoms might include:

    • Vomiting, with or without blood

    • Lack of appetite

    • Weight loss

    • Weakness and exercise intolerance

    • Pale mucous membranes

    • Anemia

    • Difficult or rapid breathing

    • Abdominal pain

  • In patients with bleeding in the respiratory tract, other symptoms might include:

    • Nosebleed

    • Sneezing

    • Coughing up blood

    • Pale mucous membranes

    • Anemia

    • Weakness and exercise intolerance

    • Difficult or rapid breathing

  • In patients with abnormal blood clotting disorders, other symptoms might include:

    • Nosebleed

    • Blood in the urine

    • Bright red blood in the stool

    • Blood in the eyes

    • Vomiting, with or without blood

    • Abnormal bruising or spotting on the skin

    • Anemia

    • Pale mucous membranes

    • Weakness and exercise intolerance

    • Difficult or rapid breathing

Causes of Dog Melena

Melena in dogs can have many causes, including:

  • Ulcers in the gastrointestinal system

  • Tumors of the mouth, esophagus, stomach or small intestine

  • Gastrointestinal infections

  • Foreign body in the gastrointestinal system

  • Disorders involving inflammation of the intestinal tract

  • Kidney failure

  • Addison’s disease

  • Drug toxicity

  • Exposure to toxins

  • Parasites

  • Liver disease

  • Pancreatitis

  • Hormonal disorders

  • Infections, cancer or foreign bodies within the lungs or nose

  • Trauma

  • Disorders involving abnormal clotting of blood

  • Cancer


You will need to give a thorough history of your dog's health, onset of symptoms and possible incidents that might have led to this condition. The history you provide may give your veterinarian clues as to where the blood is originating from.

After taking a complete history, your pet’s veterinarian will conduct a complete physical examination. Standard laboratory tests for dogs with melena can include a complete blood count (CBC), biochemistry profile, fecal examination and urinalysis.

The results of these tests will reveal how serious your dog’s melena is and can possibly point to the potential underlying cause. Additional procedures and testing may also be necessary. These can include X-rays, ultrasound imaging, endoscopy, specialized blood tests, surgery and tissue biopsies, depending on the particulars of your dog’s case.

what should your dog's poop look like?

  • blood clotting disorder
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The term for black feces that has blood in it


An in-depth examination of the properties of urine; used to determine the presence or absence of illness


The digestive tract containing the stomach and intestine


Anything having to do with the stomach


The tube that extends from the mouth to the stomach


A condition of the blood in which normal red blood cell counts or hemoglobin are lacking.

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