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Featuring Demian Dressler, DVM and Sue Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide

When to Call Your Vet About Blood in Dog Stool

Updated: December 6th, 2021


Blood in dog stool is usually caused by parasites or making poor snack choices, but it can also have more sinister roots.

Blood in dog stool is something that makes us dog lovers panic. But there is some good news! Isolated episodes of a little bloody stool is nothing to worry about, and it is only rarely a sign of cancer.

Causes of Bloody Stool in Dogs

Bloody stool can be caused by a variety of things, ranging from simple and easy to fix to more sinister.

Here are some potential causes, with the most common in bold:

  • Parasites (most commonly Hookworms or Giardia)
  • Ate something he shouldn’t have
  • Straining from prolonged diarrhea
  • Infected anal gland
  • Obstruction/blockage
  • Clotting disorder
  • Stomach ulcer
  • Irritable bowel syndrome
  • Internal bleeding
  • Stomach, intestinal, or anal gland cancer

What to Do if Your Dog Has Bloody Stool

If your dog just has a little bit of blood in, or on, the stool and is otherwise acting totally normal, it is probably nothing to worry about.

Should it happen more than once within a day or two, drop off a fresh stool sample at your vet’s office. The poop will be checked for parasites and can be sent out to a lab for even more in-depth parasite testing.

You can also send a photo of your dog’s poop to your vet to put in your dog’s file.

When to Be Concerned

Bloody stool is more likely to be a problem in these situations:

  • The stool has a lot of fresh red OR old black blood
  • Bloody stool occurs frequently
  • Your dog is also vomiting
  • Your dog is straining to defecate
  • Your dog shows signs of abdominal pain or discomfort
  • You see pale or bluish gums
  • Your dog is generally acting sick and unwell

If any of these symptoms are present in addition to bloody stool, your dog should be examined by a veterinarian.

Getting a Diagnosis

Which tests your vet runs will be based on your dog’s exact symptoms and how sick he is, but here are some options:

  • Fecal analysis
  • Blood tests to check organ function and clotting
  • A special fecal test to evaluate blood in the stool
  • Abdominal ultrasound
  • Radiographs (X-rays)
  • Endoscopy to look inside the GI tract

Can I Treat Bloody Stool at Home?

If your dog’s only symptom is a small amount of blood in or on his stool and he is otherwise perky and healthy, you can monitor him at home.

For mild cases of diarrhea, fasting your dog for 12 hours or so (no food or treats) gives his GI tract a break. Then offer a bland diet, such as plain boiled chicken and plain cooked rice, for a few days.

You can also give your dog a probiotic to help normalize his GI tract. Probiotics intended for dogs are very safe, and can be used as needed or every day.

If the bloody stool continues or gets worse, or if your dog starts showing other symptoms, it’s time to call the vet.

For more information, you can listen to this podcast episode featuring Dr. Nancy Reese, DVM PhD:

You can also read the full transcript on the episode page of Dog Cancer Answers.

Please subscribe to, rate, and review Dog Cancer Answers in Apple Podcast or on your favorite pod-catcher. It really does help the show!

Paws and wags,


PS: Feel free to share this article or the podcast itself with your veterinarian and their staff.

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