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Why does my Shih Tzu have black poop while taking antibiotics?

Updated On September 23rd, 2025

Pet's info: Dog | Shih Tzu | Male | 6 months and 11 days old | 3.3 lbs

My shih tzu hasn't been drinking or eating so we started to feed him by syringe. But just now, I saw him drinking water (still didn't touch his food). He's currently taking antibiotics because the vet set he has a very low platelet count (59). We also noticed the his poop started to be different. It became dark brown liquid and we saw black drops in it. Does this have anything to do with him taking antibiotics? Is it good or bad? Thank you!

4 Answers

Most Helpful Answer

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Answered By David Elbeze, DVM, MRCVS

Veterinarian

Published on August 6th, 2017

Black stools is usually a sign of bleeding from the stomach or small intestines, it's definitely not a good sign and is not likely to be due to the antibiotics. i would recommend taking Curt back to the vet ASAP for re-evaluation of the situation.

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    Answered By Lindsey Edwards MVB, BSc, IVCA

    Veterinarian

    Published on April 21st, 2017

    I would be concerned about black tools indicating a possible bleed. I recommend you return for a recheck on monday and take samples of both types of stool for a full assessment. Continue with the sensitivity diet and encourage as much fluids as possible, a probiotic may also help such as fortiflora or canikur

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    Answered By Dr. Strydom, DVM

    Veterinarian

    Published on April 17th, 2020

    This is very serious. Black stools mean that it is digested blood. So, he is still having some bleeding somewhere in his intestinal tract. You can deworm him again - that would be a good idea. If you are able to get him some probiotics I would give him that and also start putting him on regular dog food. You should also start giving him some Omeprazole 10mg once per day. It is a human drug and you can likely buy it at your local pharmacy. I would give that once per day for two weeks and then stop. As long as he is eating that is a good sign.

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    Answered By Christie Long, DVM

    Veterinarian, Certified Veterinary Acupuncturist

    Published on June 6th, 2018

    I'm not sure why you posted the picture of the antibiotics. That is a commonly used antibiotic in vet med, and I doubt that it's the cause of what's going on with your dog. I'm especially concerned about the dark feces and pale skin color - to me that suggest bleeding into the GI tract and resulting anemia. I suggest you get him back in for emergency care immediately as he seems to be getting worse and not better.

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