Call your vet
Bright red blood (hematochezia) usually comes from the lower gut, such as colitis or straining. Black, tarry stool (melena) means digested blood from higher up and is more concerning. Bloody diarrhea with vomiting in a puppy can be parvovirus.
See a vet now if you notice:
- Black, tarry stool or lots of blood
- Vomiting as well, or not eating
- Lethargy, weakness or pale gums
- A puppy, senior or dog with health problems
- Possible toxin exposure (rat bait, medicines)
Possible causes
- Colitis, straining or anal gland problems (bright red streaks)
- Hemorrhagic gastroenteritis ("raspberry jam" diarrhea)
- Parvovirus in unvaccinated puppies
- Parasites, toxins (rat poison), ulcers or tumors
What to do
- A small streak in an otherwise healthy dog: call your vet and watch closely.
- Lots of blood, black stool, vomiting, weakness or a puppy: go to a vet now.
- Take a photo and bring a sample.