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My pet has dark diarrhea after Pepto Bismol. Should I go to the vet?

Updated On September 23rd, 2025

Pet's info: Dog | Pug | Male | neutered | 12 years and 5 months old | 40 lbs

My pet has been having diarrhea since for about 33 hours now. It was yellow orange before then I gave some peptol bismol and now it’s is very dark brown almost black. He is eating rice and ground beef not lethargic and not dehydrated. Should I take him to the ver

1 Answer

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Answered By Dr. Heidi DVM, CVA, CCRT, CVTP, CVSMT, CVCH

Veterinarian, Certified Veterinary Acupuncturist, Certified Canine Rehabilitation Practitioner

Published on June 4th, 2018

I'm sorry to hear that Oliver is having diarrhea. One of the potential side effects of Pepto bismol is that it can cause a very dark discoloration of the stool. So, that may be the reason for the color change that you have noticed. If Oliver continues to eat and feel well, then you may be able to continue with the bland diet at home. If he does well with a bland diet and his diarrhea resolves, then you can slowly transition back to his normal diet over a few days. Diarrhea that continues for more than a few days, or is associated with blood in the stool, vomiting, lethargy or a poor appetite is a reason for a visit to your veterinarian. I have attached a couple of links below that might be useful for you. Petco Pet Education Center, formerly Petcoach.co/article/most-common-causes-of-diarrhea-in-dogs/ Petco Pet Education Center, formerly Petcoach.co/article/6-things-you-can-do-at-home-if-your-pet-has-diarrhea/ Good luck! I hope that was helpful and that he feels better soon. Thanks for using Petco Pet Education Center, formerly Petcoach.

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