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10 Causes of Blood in Dog Poop and Common Treatments

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Layne worked as a wildlife rehabilitator and medical intern for several years before becoming a licensed veterinary technician (LVT).

Why is there blood in my dog's poop?

Why is there blood in my dog's poop?

What if Your Dog Is Pooping Blood and Vomiting?

Finding blood in your dog's poop can be quite traumatizing. In human medicine, we are taught that blood or bleeding is something that often needs to be checked out by a doctor unless you have a history of non-life-threatening conditions like hemorrhoids.

In dogs, bloody stool can indicate a variety of conditions, from a benign rectal polyp to more serious conditions like cancer or acute poisoning. We will go over each of these conditions and talk about treatment and methods of diagnosis as well as how to identify symptoms.

Causes of Blood in Dog Poo

  • Foreign body ingestion and impaction
  • Parasites
  • Viral or bacterial infections
  • Colitis or hemorrhagic gastroenteritis
  • Digestive upset or allergy (food-related)
  • Cancer, masses, and tumors
  • Autoimmune disorders
  • Medications
  • Poisoning

The most common causes of bloody stool in dogs are parasites, which are usually acquired from the environment; colitis, which may be triggered by stress or the ingestion of unfamiliar food; and foreign body ingestion—eating objects that irritate the GI tract and may cause dangerous soft tissue perforation. Bloody stool might be accompanied by vomiting, look like pure blood, look like coffee grounds, be smelly, have bits of what looks like soft tissue in it, and more. Find out what to look for.

When to see a veterinarian.

When to see a veterinarian.

Does My Dog Need to See a Vet?

This is where you have to "triage" your dog and do some investigative work. It is always wise to take your dog to the vet for bloody stool. If you have the money and the resources to do so, take your dog in! Better safe than sorry (some conditions are serious and life-threatening).

It is also important to "triage" your dog and understand when bloody stool is considered an emergency. In all cases, bring a stool sample to your vet if you can.

How Is Your Dog Acting?

If your dog is lethargic, feverish, refuses to eat, is vomiting or nauseated, is withdrawn or acting unlike him or herself, has preexisting health conditions, has a history of ingesting random things, may have been exposed to poison, or is under 6 months of age (puppy) or geriatric, you will want to go to the vet!

Is It Hematochezia or Melena?

  • Hematochezia: Hematochezia is bright red, fresh blood (often in droplets) and comes from the lower intestines—the colon and rectum. Sometimes the presence of a few droplets of fresh blood may be transient and resolve on its own.
  • Melena: Melena comes from the lower or upper GI. tract (esophagus, stomach, small intestine) and presents as a tarry-black stool; it tends to take on the appearance of "coffee grounds," meaning that the blood has been digested. Melena is harder to recognize than hematochezia and may indicate more serious conditions.

How to Bring a Stool or Fecal Sample in to Your Vet

You will want to collect the freshest sample you can find (within a few hours). It is also a good idea to bring in a sample of any "regular" stool in addition to the stool containing blood. You will need to refrigerate the sample if you cannot transport it in immediately—parasite eggs and oocysts may morph and be missed during examination if not refrigerated.

Sample size: Only one teaspoon of feces is needed for a sample.

Veterinary clinics will run a "fecal" or do a fecal flotation or fecal smear to take a look at what is in your dog's stool. They work with a very small pea-sized sample of feces in this case. But because you want to provide them with a good sample size, you will need the following:

  • A disposable spoon, a shovel, or a gloved hand (or a fecal collector from your vet)
  • A clean, plastic sandwich bag or disposable/recyclable container or plastic cup
  • Poop


  1. Collect roughly 1 tablespoon (better too much than too little) of the regular feces and the bloody stool using separate collection methods (only if both are available). Use a clean collection device (if you use a stick or something "contaminated," you may introduce material into the sample).
  2. Place it in a sealed carrying container (baggy or Saran wrap if in a cup) and transport it to the vet ASAP.
  3. Do this for both the regular stool sample (if available) and the bloody stool sample (more important). Use a separate collection instrument for each sample and do not mix the samples.
  4. You may want to refrigerate the samples in a leak-proof bag (warning: at your own discretion) if you cannot transport the sample into the clinic in time.
  5. WASH YOUR HANDS and clean any contaminated surfaces immediately. Accidental fecal-oral transfer of parasites can occur.
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Read More From Pethelpful

What Is a Fecal Flotation or Fecal Float?

Your veterinarian will likely run a fecal float. They will use a solution—sodium nitrate, sugar, or zinc sulfate—to suspend any parasites or parasite eggs and cysts for microscopic analysis. A centrifuge may be used or sedimentation may be conducted depending on the type of parasite suspected (eggs and cysts have different weights and suspend differently in different solutions).

How to Collect a Fecal Sample (Wash Hands or Wear Gloves)

1. Ingestion of a Foreign Object

If you've taken the time to look closely at your dog's stool, you may notice that he or she simply chewed up a red Kong into a million tiny pieces and passed it in their poop. Or, your dog may have eaten artificially dyed red kibble bits, and the food dye may have produced discolored poop. Check your surroundings.

When Is It an Emergency?

If your dog ingested something risky and you've found evidence of such (a rawhide is missing, a plastic toy was destroyed, a rock was swallowed), you will want to see the vet. Perforations in the stomach may result in melena (darker blood) or bright red blood. Any time a foreign object is ingested, your dog is at risk of impaction. That means that the object can impact sections of the GI tract and could potentially cause necrosis of the tissues.

Symptoms to Look Out For

If severe, your dog may stop eating and drinking, may have vomiting and diarrhea, and will be unable to pass the object. These cases are emergencies and often require diagnostic imaging (x-rays, or other), palpation, and sometimes emergency surgery if the object can't be passed. If the vet determines that your dog can pass the debris, you will likely be instructed to watch them at home and feed them stool-softening agents like unflavored, canned pumpkin to help with motility.

2. Parasites

Parasites are another common cause of bloody poop. Most dogs have hosted a parasite in their lifetime (fleas serve as the intermediate host for the tapeworm). Shelter dogs go through heavy deworming protocols to prevent the spread of parasites and to clear anything that they may have acquired from their previous environment or from mom (nursing, close proximities).

Tapeworms, hookworms, whipworms, roundworms, and giardia and coccidia are very common parasites in dogs. Adult roundworms resemble strings of spaghetti, and tapeworms look like cooked rice—these are two common parasites that may be visible in your dog's stool. Sometimes, they are only detectable via fecal exam.

Giardia and Coccidia

Giardia and coccidia are notorious for causing bloody stool and foul odor. The affected dog will also present with diarrhea and vomiting. Litters of puppies are particularly prone to giardia and coccidia, which they often acquire from their environment. Active dogs that play in large bodies of stagnant water or drink stream water are also at risk.

  • Giardia cysts are extremely hardy and resistant. They may be found via a direct fecal smear or an ELISA antigen test kit. Fenbendazole and metronidazole are commonly prescribed to treat Giardia.
  • Coccidia (caused by a protozoa) is acquired similarly (environmental) and is actually more risky if left untreated and undiagnosed. Piles of stool may also appear foamy and white and have a foul odor. Coccidiosis can be treated with Albon (sulfadimethoxine) or off-label drugs.

Caution: These parasites are zoonotic (can be acquired by humans and other animals) and can be acquired via fecal-oral transmission, so take extreme caution with small children around your affected pet. Wash your hands and avoid eating near contaminated areas.


Parvovirus is an extremely dangerous, highly contagious virus. Puppies under 6 months of age should be receiving their core/combo vaccine for parvovirus starting as early as 6 weeks (shelter med) to 2 months of age.

This extremely hardy virus is shed in the feces and spreads via fecal-oral transmission. Black and tan breeds are especially at risk—Dobermans, Rottweilers, German Shepherds. These puppies exhibit lethargy, nausea and vomiting, diarrhea, or bloody diarrhea. If you notice these symptoms in your puppy, it is extremely critical that you see a veterinarian and do not attempt to let it resolve on its own. It is often fatal if left untreated.

How Is Parvovirus Diagnosed?

Your puppy can be diagnosed rather quickly with a simple ELISA snap test (ELISA is an acronym for enzyme-linked immunosorbent assay) that can lead to a positive or negative result within minutes or a fecal PCR test (polymerase chain reaction). PCR tests, though more accurate, often get shipped out for laboratory analysis.

Your veterinarian may order blood work and other chemistries, upon which dehydration, electrolyte imbalances, and low white blood cell count (a prominent indicator of the condition) may be observed. Puppies may also present with fever, dehydration, weight loss, and an elevated heart rate or, in severe cases, hypothermia.

Supportive Care Is Necessary

Puppies often require hospitalization and supportive care—IV fluids, antibiotics, nutritional supplementation, anti-nausea, and anti-diarrheal meds. Sometimes they require transfusions as well. If left untreated, this conditions is often fatal.

Parvovirus in Puppies

3. Colitis and Hemorrhagic Gastroenteritis

Stress colitis is another common cause of blood in dog stool and originates from the large bowel, causing diarrhea. Your dog may strain and pass bright red blood. The causes of stress colitis vary, but they include environmental stress, infections, parasites, allergies, physical trauma, autoimmune disorders, and IBS.

Colitis: Umbrella Term for Large Bowel Upset

Colitis is often used as an umbrella term for various intensities of GI upset in dogs, so diagnosis and treatment will vary. This may include anything from biopsies and ultrasounds to simple dietary changes or anti-anxiety prescriptions. Some dogs even exhibit bouts of stress colitis when their owners travel. Whatever the cause, it is important that you get it diagnosed to prevent long-term complications in addition to dehydration.

4. Hemorrhagic Gastroenteritis (HGE)

HGE is an acute disorder in dogs and presents with vomiting and bright-red, bloody diarrhea. This is especially common in toy breeds. This condition is said to be idiopathic or immune-mediated. It can also be caused by the ingestion of toxins or may accompany pancreatitis.

Blood work and chemistries may be run, and radiographs may be ordered by your veterinarian. Supportive care is necessary and will include fluids and gastrointestinal protectants or sucralfate. Clotting disorders may progress if left untreated and can lead to death.

Food allergies is a common cause of GI upset.

Food allergies is a common cause of GI upset.

5. Dietary and Food Allergies

Whether you recently changed your dog's food or your dog is currently sensitive to whatever you are feeding them, you may see fresh blood in your dog's stool. The blood may also be accompanied by mucus or bouts of diarrhea. If the allergen is not properly identified, bloody stool may become more persistent and cause secondary complications.

Allergies in dogs, especially food-related, may present with skin allergies. If your dog is itchy, has hot spots or hair loss, and suffers from diarrhea and bloody stool, it's possible that they have a food sensitivity. Work with your vet. You may also want to rule out any new treats or human foods that your dog is eating.

Purebreds Are Prone to Allergies

Certain purebreds are prone to food allergies. Irish Setters, for example, are notorious for being diagnosed with Celiac disease/severe gluten intolerance. Gluten is used as a binding agent in dog food and contributes protein to any dog food label, but the impact of gluten on the small intestine can wreak havoc in some breeds. Corn, chicken, wheat, fish, and dairy as well as preservatives and certain dyes may cause allergies as well.

6. Cancer, Masses, Tumors

Cancer—masses, tumors, and rectal polyps—may cause bright red blood to appear in dog stool. Tumors and polyps are highly vascularized, and depending on the location of the mass, may cause bright red or dark (like coffee grounds) blood in the stool. Your vet may do a rectal exam on your dog to check out its anal glands as well for "perianal tumors"—anal gland carcinoma is a possibility; though slow-growing, it has the potential to metastasize. These glands sit on either side of the anus.

Lymphoma and adenocarcinoma are common cancers that can metastasize and affect the intestinal tract in dogs. These dogs may also have vomitting and diarrhea, experience weight loss, or may become constipated.

Diagnosis and treatment often involves a physical exam, blood work, x-rays, MRI, or ultrasound. Treatment options may vary depending on location and severity and may involve surgery, chemotherapy, radiation therapy, or palliative care.

7. Autoimmune Disorders

Several autoimmune disorders may cause bloody stool in dogs. Immune-mediated hemolytic anemia, lupus, and thrombocytopenia are a few autoimmune disorders that occur in dogs which can affect coagulation or may resemble common bleeding disorders in humans. Inflammatory bowel disease or IBD is most likely to cause bloody poop in dogs.

8. Inflammatory Bowel Disease (IBD)

Inflammatory bowel disease is not well understood but it is characterized by inflammation of the intestinal wall. Most dogs with IBD exhibit an allergic-type reaction in the intestinal tract which further prevents the absorption of nutrients—resulting in vomiting and diarrhea.

Allergies result from an overactive immune system, that is, the body is hyper-reacting to a foreign substances, often to the detriment of the affected. High fiber diets and hypoallergenic foods may help sufferers. It is important to manage IBD in dogs so that it does not progress to cancer.

9. Medications

The side effects of certain medications may cause bloody stool in dogs, so it is important to work with your veterinarian. This may occur after your dog has been treated for certain conditions or after surgery and has been sent home with common meds like NSAIDs. If your dog has recently undergone surgery, it is not uncommon to see abnormal stool, especially in cases where the intestinal tract or colon was worked on—your vet should have mentioned this in aftercare instructions.

NSAIDS (Non-Steroidal Anti-Inflammatories Drugs)

Pets that have a history of stomach or intestinal ulcers or are on another medications should are unlikely to receive NSAIDs from your vet due to the risk of side effects like diarrhea, bloody or tar-colored stool, as well as other complications. FDA-approved NSAIDS for dogs include Carprofen (Rimadyl, Carprieve), Deracoxib (Deramaxx), Meloxicam (Metacam), and Robenacoxib (Onsior). NSAIDs are not good for long-term use in dogs.

10. Poisoning

Long-acting anticoagulants like warfarin prevent clotting and are or were used for many years in mouse and rat poison and human medication. Symptoms after ingestion may be delayed 2-3 days and internal bleeding will occur. Evident abnormal signs include diarrhea (with blood), nose bleeds, bleeding from the gums, bruising or petechiae, and weakness. Most pets require treatment with Vitamin K1 for 30 days and NEED to be seen by a veterinarian immediately upon the first indications of toxicity.

Secondary poisoning via the ingestion of rats and mice that have been poisoned (bromethalin rodenticide toxicity) causes neurological symptoms in dogs. Some symptoms include muscle weakness, ataxia, paralysis, and seizures, and may have a delayed onset. Toxic doses of bromethalin are estimated to be 2.5 mg/kg for dogs.

Rat Bait or Rodenticide Poisoning

Should I Be Worried?

Sometimes dogs receive acute rectal injuries or fissures for one reason or another, and the bloody stool resolves on its own. In most every other case, you need to work with a veterinarian for a proper diagnosis. Some of these conditions require emergency veterinary medical care as well. Do not attempt to treat your dog at home unless you were sent home with take-home instructions by your vet.

Feel free to ask questions in the comments below, but be advised that I cannot legally diagnose, prognose, prescribe, or suggest treatment—only your veterinarian can do that.


  • Joanna M. Bassert and John A. Thomas. McCurnin's Clinical Textbook for Veterinary Technicians. Elsevier Inc.: 2014.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2019 Laynie H


Laynie H (author) from Bend, Oregon on January 15, 2019:

Hi Ellison, thanks for the feedback. So glad to hear your yorkie passed peacefully in his sleep—that is truly the best, as it's hard to decide when the right time is. It's less stressful by far than going through the difficult decision of euthanasia. We had a black lab-rottweiler-chow mix who lived to be 14. She had a huge mass, had a splenectomy, and then was showing symptoms of internal bleeding months later. She had a great final 2 weeks before we had to make the hard decision when we found internal bleeding. Always hard losing pets. They are so wonderful!

Ellison Hartley from Maryland, USA on January 15, 2019:

This is so good. My little yorkie who lived to be 12, had blood in his stool for a day or two before he died. Not a lot, just a little. He was thin, but I attributed it to age and not the greatest teeth anymore. He just went to sleep and didn't wake up. He had a good life, and I guess if you have to go that's a peaceful way to do it,

Thanks so much for sharing your knowledge in such an easy to undertand way!

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