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My dog has black, tarry diarrhea and won't eat. Is it serious?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed | Male | unneutered | 9 years and 1 month old

My dog has black diarrhea that is like tar. He also won't eat, not even bread.

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4 Answers

Most Helpful Answer

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Answered By Andrea M. Brodie, DVM

Veterinarian

Published on February 15th, 2016

Black tar-like diarrhea is a sign of digessted blood and a serious condition that needs to be checked out by a veterinarian. This could be caused by ulcers, a tumor an injury to the upper airways with blood being swallowed, or an esphageal bleeding. Your dog needs to be seen by a veterinarian now, who will do blood tests, radiographs. Your dog may have to be hospitalised.

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41Pet Parents found this answer helpful

Other Answers

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    Answered By Dr. Massimo Orioles, DVM, Cert AVP, MRCVS

    Veterinarian

    Published on

    Black tar diarrhea may be compatible with gastrointestinal hemorrhage, usually in the first part of the gastrointestinal system. Inappetence could be as well compatible with a gastrointestinal disease. I would strongly recommend to take him to your veterinarian as soon as possible for a check up and more investigation performed to identify the underlying cause. Your veterinarian may want to perform radiographs or ultrasound of the abdomen.

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    Answered By Dr. Elizabeth

    Veterinarian

    Published on June 9th, 2019

    Black tarry stool can indicate blood within the gastrointestinal system and this is serious. See this link about dog feces: https://www.petcoach.co/article/the-real-scoop-what-is-your-dog-s-poop-telling-you/ I recommend to have Harley examined by a veterinarian today. It's best to play it safe. Best of luck.

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    Answered By Dr. Elizabeth

    Veterinarian

    Published on June 26th, 2019

    Rita needs to be examined today. Black stool can indicate bleeding in the gut which is very concerning. Here is a link about stool: https://www.petcoach.co/article/the-real-scoop-what-is-your-dog-s-poop-telling-you/ Bring in a sample of fresh stool for examination. Best of luck.

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