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Why is my dog's poop bloody and hard after food change for allergies?

Updated On September 23rd, 2025

Pet's info: Dog | Bull Terrier | Male | unneutered | 8 months and 10 days old | 48 lbs

Dog has blood at end of poop stool, has hard stool and eats fine and still energetic, had to recently change food due to allergys and also giving benadryl

1 Answer

Most Helpful Answer

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Answered By Dr. Macartney, BVet Med, MRCVS

Veterinarian

Published on August 3rd, 2017

I am very sorry to hear that Marshall is experiencing this issue, I am sure it is unsettling. From what you are describing, a normal bowel movement which has fresh blood in it, it sounds as though Marshall has colitis, or inflammation of the last portion of the large intestines. There are several causes of colitis in dogs, ranging from bacterial infections, parasite infestations, IBD, or ingestion of contaminated food. In this situation it seems to me that the most likely cause is the recent change in food Since you have only noticed one such episode I would continue to monitor Marshall at home. Provide a bland diet of boiled boneless chicken breast and white rice and plenty of fresh water. Then slowly change back over to the new food. If the episodes continue, if Marshall becomes depressed, passes large amounts of blood, vomits, or seems very uncomfortable take Marshall to see his vet. I hope this answer was helpful and more importantly that Marshall feels better soon. Warmest regards to you both.

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