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Bloody Diarrhea in Dogs: Its Causes, Diagnosis and Treatments

I am a veterinarian who is trying to bring a new taste to people's lives.

A Beautiful Dog Playing with its Owner

A Beautiful Dog Playing with its Owner

Diarrhea is like the passing wind: it comes, makes noise, and slowly leaves without doing any serious harm. Mostly, the dog recovers without any specialized care. But the real problem starts when the owner complains about the presence of blood in the stool. Bloody diarrhea or hemorrhagic gastroenteritis can be a fatal condition that requires immediate and distinctive care. Most vets treat bloody diarrhea as an emergency and advise the owners of regular monitoring and check-ups. So, if your dog or any of your pets has its blood oozing out into the feces, you must reach out to your veterinarian!

Difference between Malena and Hematochezia

Blood is composed of red blood cells. These RBCs are sacks of hemoglobin. Hemoglobin is a protein that can be digested by enzymes of the alimentary canal. Since most digestion takes place in the upper part of the alimentary canal (stomach & small intestine), the blood that comes into the lumen of the stomach and small intestine is broken down and digested by the enzymes and appears black in the doo-doo. This condition is called Malena. Malena indicates a problem in the former part of the digestive system.

The second condition is when the owners observe fresh blood or red-colored poo. The latter part of the digestive tract (large intestine) is affected in this scenario. Excreta is bright red and thin. Blood is undigested as the large intestine is involved in absorbing water and minerals. This condition is known as Hematochezia.

Rarely, the poo may contain both digested and undigested blood. Differentiation between Malena and Hematochezia is the first step in diagnosing the underlying disease and prescribing treatment.

Causes of Bloody Diarrhea

Bloody diarrhea is not a disease in itself. It is the outcome of other diseases and conditions that are both; infectious and non-infectious. Important causes are as follow:

Bacterial and Viral Infect

Bacteria and viruses are the most common infectious causes of bloody poo. The most common cause of bloody scat that I have observed during my veterinary practice is the infection due to parvovirus. The onset of the disease is rapid and causes nausea, dehydration, fever, and bloody diarrhea. Furthermore, bacteria, such as Salmonella and E. coli, are the notorious causes of blood-soaked stool.

Intestinal Parasites

Intestinal parasites live and dwell in the intestine of dogs. These parasites suck blood and leave open wounds. The blood from these wounds ooze into the digesta and ultimately comes out through feces. The most common parasites in this regard are Giardia, Hookworm, Pinworm, etc.

Foreign Body

A foreign body inside the gut can cause internal bleeding and severe injuries to the digestive tract. The foreign bodies found by the vets include bones, needles, clothes, pins, pieces of plastic and metal, etc.

Particularly bones and needles are occasionally found inside the GIT of dogs. Their sharp edges and small sizes make them exhausting to locate and remove while causing enormous damage to the mucosa.

Vets Performing Surgery in Order to Remove Foreign Bodies from GIT of a Dog

Vets Performing Surgery in Order to Remove Foreign Bodies from GIT of a Dog


An ulcer is a sore or wound in the inner wall of the gut. A sore or a wound exposes the intestinal contents to the blood supply of the GIT. As a result, the blood may come out of the capillaries and get mixed with the excreta.


Colitis is the inflammation of the colon. The colon is a part of the large intestine. The reasons that dogs develop colitis are diverse. It can be due to infectious or non-infectious reasons. But one of the most common causes is stress. Stress due to temperature, changes in habitat, or distant traveling may result in colitis. As the condition aggravates, the stool becomes stained with blood and mucus.


Although cancer of GIT is uncommon, it can easily cause bloody diarrhea. Tumors formed inside the GIT are fragile and rupture often. With an extensive blood supply, the rupturing of the tumor results in extensive internal bleeding.

Improper post-surgical care and Trauma

The intestinal mucosa of a dog is very delicate, and any trauma or injury to it can be life-threatening. In the case of any harsh blow or severe external injury to the stomach or belly, the intestine may rupture or break. Furthermore, any sharp objects that pierce the belly from the outside can damage the GIT. This injury not only induces external bleeding but can also engender bloody stool.

Surgery of GIT is frequent in the case of foreign bodies, tumors, etc. As the gut is fragile, post-surgical care is vital to the survival of the animal. In case of any negligence on the part of the owner or the veterinary staff, the sutures may open, and bleeding can start. GIT has an extensive blood supply. Tearing a small vessel can induce very rapid bleeding. In this particular case, the owners must approach the vet swiftly, as any delay can be life-threatening.

Change in feed/ diet

A frequent and rapid change in the diet is not advised as it can upset the balance of GIT. This overnight change kills beneficial bacteria and disrupts the normal process of digestion. Although diarrhea is frequent in this case, the incidence of bloodstained feces is low and occurs rarely.

Side-effects of Medication

Almost all medicines have some side effects. These side-effects can be minor but can also cause deaths. Bloody diarrhea is a common side-effect of prolonged antibiotic therapy.

Other Causes

There are other uncommon causes of bloody diarrhea. These causes include liver& kidney diseases, toxins, genetic & autoimmune disorders, etc.

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When to approach a Vet

If the owner sees a single drop of blood in the poo or even suspects anything resembling the blood in scat, he/she must visit the vet for a complete check-up of the suspected dog.

A Vet Taking Vitals of a Dog

A Vet Taking Vitals of a Dog


The diagnosis of bloody diarrhea is the detection of a specific disease condition. The goal is to identify the actual cause of the bloody poo.

If the owner suspects the presence of blood in the feces, the vet performs a fecal occult blood test ,also known as FOBT. FOBT is a qualitative test that confirms the presence or absence of blood traces in the dunk.

The next step is to detect the primary cause of bloody diarrhea. For this reason, the vet asks the owner about the complete history. The history includes

  • Time of the onset of disease
  • Nutritional status
  • Bedding and environmental conditions
  • Previous medication

Then the hospital staff will check the vitals of the patient. The readings noted include temperature, pulse, dehydration status, capillary refill time (a test done to assess anemia), and general posture.

Keeping in mind the values of vitals and visualizing the general condition, the vet prescribes laboratory tests for confirmatory diagnosis. The lab tests include CBC, PCV, liver & kidney function tests, ultrasounds, and X-rays.

On the basis of these tests, the vet makes a confirmatory diagnosis and prescribes a suitable treatment.

Administration of a IV injection in a Dog

Administration of a IV injection in a Dog

Is bloody diarrhea an Emergency situation?

Bloody diarrhea or HGE is an emergency by all means. It should never be ignored and proper care should be given on time.


After identifying the primary cause, the veterinarian prescribes the best suitable treatment. Treatment mostly includes

  • Firstly, the vet advises intravenous infusion of normal saline and minerals. Dogs suffering from bloody diarrhea are dehydrated with acute loss of electrolytes. The IV infusion helps in the replenishment of lost water and minerals. Vets don't advise IV infusion of dextrose as it encourages the growth of bacteria.
  • Antibiotic therapy, if the causes are due to bacterial and viral infections. In the case of viral attacks, antibiotics help counter secondary bacterial infections.
  • Surgery is advised if any foreign body and tumor are visualized in the gut. A foreign body is very harmful to the fragile mucosa of GIT, so the surgery must be performed at the earliest.
  • Antiparasitic or anthelmintics for parasitic infestations
  • Giving soft diet, proton pump inhibitors for ulcers along with liver & kidney tonics
  • Suspension of previous medication (as the condition can be the result of side effects of certain medicines).
  • Blood transfusion in case of life-threatening situations.
Grooming and Cleaning of a Dog in Progress

Grooming and Cleaning of a Dog in Progress


To save their dogs from any serious complications, the owners must remain cautious and take preventive measures. The measures include

  • Complete vaccination of puppies
  • Provision of clean, pathogen-free, and nutritious feed
  • Regular cleaning and grooming
  • Regular walk and exercise
  • Frequent check-ups and on time deworming
  • Isolation of affected in case of multiple pets and dogs


Will bloody diarrhea recover on its own?

No, bloody diarrhea is a consequence of a gruesome condition and doesn't recover by itself.

How long will my dog or cat take to recover from bloody diarrhea?

Well, it depends upon the severity of the condition and the health status. Generally, the complete recovery takes a week or two.

What is the cost of treatment?

The cost varies widely. In case of infection, the spending will be around 500-700USD. But if the dog requires surgery, then the total expenditure may escalate to thousands of dollars.

What is the difference between bloody diarrhea and hemorrhagic gastroenteritis?

Both have the same meanings. Bloody diarrhea is the term used by men in the street, while the vets use the term HGE to define bloody diarrhea.


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.

© 2022 Abdullah Iqbal

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