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Puppy diarrhea with blood after negative vet test. What's wrong?

Updated On September 23rd, 2025

Pet's info: Dog | Beagle | Male | neutered | 8 months and 21 days old | 24 lbs

My 8 month old beagle has sudden diarrhea, which I first noticed 5 days ago when he began to go in his crate after being potty trained. We went to the vet and did a fecal, which came back negative but he was given a dewormer just in case. I started him on boiled chicken and rice today. He is eating and acting normal. What is the deal? I recent found some blood in the water stool this evening.

1 Answer

Most Helpful Answer

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Answered By Dr. Strydom, DVM

Veterinarian

Published on July 3rd, 2019

Unfortunately pretty much anything can cause diarrhea in dogs. So, I can't tell you what is causing his issue. Could be anything from intestinal parasites, to inflammatory bowel disease to a food allergy. I suggest you call and ask your vet if they checked for whipworms and protozoal parasites (ie: giardia, coccidia). Both are not treated by the regular, general dewormer we use so could still be a possibility. They are often overlooked if the fecal was run inside the hospital instead of being sent off to a laboratory. Maybe sending a fecal to a laboratory would not be a bad idea if that was not done. You can do it yourself as this is the same laboratory your vet would use. If the results are positive you can call your vet to get treatment. ( https://www.idexx.com/en/veterinary/fecalchek/ ) In the meantime, I suggest you start him on a probiotic - one made for dogs - I like Fortiflora. One packet on his food daily. It is very palatable so they like to eat it. It comes with 30 doses and I would do the whole 30 day course. It won't hurt and may help. ( https://www.amazon.com/Purina-Veterinary-Fortiflora-Nutritional-Supplement/dp/B001650NNW?th=1 ) Also, I have had HUGE success with people switching diets to Purina Sensitive Skin and Stomach food on dogs with chronic diarrhea. It really has worked wonders on some of my patients. ( https://www.proplan.com/dogs/products/focus-adult-sensitive-skin-stomach-salmon-rice-formula ) Really, though, in a puppy/young dog parasites is the number one cause for diarrhea so please do a laboratory run fecal test.

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