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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 a 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 is a serious 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 pet has its blood oozing out into the feces, you must at once reach out to your veterinarian.

Difference between Malena and Hematochezia

Blood is composed of red blood cells that can be digested by the enzymes of the digestive tract. 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 mainly involved in the absorption of water and minerals. This condition is known as hematochezia.

In highly unusual circumstances, it is possible that the poo may contain both digested and undigested blood. Differentiation between Malena and Hematochezia is the first step in the diagnosis of the underlying disease and prescription of treatment.

Causes of Bloody Diarrhea

Bloody diarrhea is not a disease in itself. It is the outcome of other diseases that are either infectious or noninfectious. Important causes are listed as follows

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 parvovirus. The onset of the disease is rapid and causes nausea, dehydration, fever, etc. in addition to bloody diarrhea. Furthermore, bacteria such as Salmonella and E. coli are also 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 is seen in the feces. The most common parasites in this regard are Giardia, Hookworm, Pinworm, etc.

Foreign Body

A foreign body inside the digestive tract of an animal can cause internal bleeding and severe injuries to the digestive tract. The common foreign bodies diagnosed by the vets include bones, small 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 difficult to locate and remove while causing enormous damage to the mucosa of the intestine.

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, stool become stained with blood and mucus.


Although cancer of GIT is uncommon, it can easily result in gastrointestinal hemorrhage. Tumors formed inside the GIT are fragile and rupture often. With an extensive blood supply, the cancerous mass once ruptured results in extensive internal bleeding.

Improper post-surgical care and Trauma

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

Surgery of GIT is common in the case of foreign body, tumor, etc. Owing to the fragility of the gut, the post-surgical care is vital to the health of the animal. If adequate care is not given to the animal, the sutures may open and bleeding can start. GIT has a very rich blood supply. Tearing a small vessel can induce very rapid bleeding. In this particular case, the owners must approach the vet swiftly to save the life of the animal.

Change in feed/ diet

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

Side-effects of Medication

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

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Other Causes

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

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 the specific disease condition. The goal of the vet is to identify the actual cause of blood-stained 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 etc.

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

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

On the base 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 identification of the primary cause, the veterinarian prescribes the best suitable treatment. Treatment mostly includes

  • In almost all cases, the vet advises intravenous infusion of normal saline along with 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. The infusion of dextrose is not suggested as it may encourage the growth of bacteria.
  • Antibiotic therapy in case of bacterial and viral infections. In the case of viral attacks, antibiotics are used to 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 serious condition and don't recover by itself.

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

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

What is the cost of treatment?

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

What is the difference between bloody diarrhea and hemorrhagic gastroenteritis?

Both have same meanings. Bloody diarrhea is the term used by men in street while 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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