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Why is my dog's watery poop bright red after eating new food?

Updated On September 23rd, 2025

Pet's info: Dog | French Bulldog | Male | unneutered | 1 year and 11 months old | 23 lbs

Lou has had watery bowel movements since about 3 this afternoon so not quite 10 hrs. But it seems to have some red in it, its bright red. He had some different dog food this morning. Also he has been playing and drinking and wanting to eat (but im withholding food)

1 Answer

Most Helpful Answer

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Answered By Laura Johnson VMD

Veterinarian

Published on December 28th, 2017

Hi, thanks for using Petco Pet Education Center, formerly Petcoach! Poor Lou! Causes of diarrhea are: intestinal parasites, viral or bacterial infections, intestinal disease (food allergies or inflammatory bowel disease), pancreatitis, food intolerance'new treats/sudden food change and eating something gross outside. It is very possible the new food you gave him in the morning is causing the diarrhea. The bright red in the stool is likely blood which indicates inflammation in the colon. I agree withholding food for 12-24 hours is a good idea. I would start feeding with a bland diet of boiled chicken or hamburger with rice. Feed 1 cup per 20 lbs per day until 1-2 normal stools then put him back on his OLD dog food. If you want to try the new food again wait until his stools have been normal for 2 weeks then SLOWLY transition him to the new food over several weeks. If diarrhea starts again then he can not tolerate the new food. If the diarrhea persists I recommend taking him to your Vet for an exam and medications. I hope this helps and I wish Lou a speedy recovery!

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