Blood in the stool in dogs

| |

The presence of blood in the dog’s stool can manifest itself in two ways:

  • Either it is blood in kind in the form of red traces mixed with the stools and we then speak of hematoch├ęzia .
  • Either it is digested blood and the stools are dark, almost black. We then speak of melena.

In either case, the presence of blood in the stool is abnormal and should not be taken lightly. Various conditions can be the cause.


Whether or not the blood is digested depends on where it comes from.

In the case of hematochezia, the blood is present in nature, undigested. This means that it comes from the lower part of the digestive tract: colon, rectum or anus.

The possible causes are:

  • Inflammation of the walls of the digestive tract such as enteritis and / or recto-colitis, of bacterial or viral origin in particular. The parvovirus eg typically causes bloody diarrhea in puppies or unvaccinated adult dogs.
  • Presence of parasites if the dog is not dewormed regularly.
  • Presence of tumors in the lower part of the digestive system. A tumor can bleed and cause the presence of blood in the stool.
  • Damage to the digestive system in the event of a foreign body wounding, cutting or stinging, for example.

In the case of melena , the blood has been digested. The bleeding therefore comes from the upper part of the digestive tract: mouth, esophagus, stomach, upper part of the intestine.

The most common causes are:

  • Inflammation of the esophagus, stomach and / or intestine: severe esophagitis or gastroenteritis with possible presence of ulcers.
  • Injuries to the mouth or nasal cavities.
  • Tumor in the upper part of the digestive system.

Some conditions can cause both hematology and melena to occur. This is particularly the case with coagulation disorders, in certain diseases or in the event of intoxication with anti-coagulants (rodenticides) for example.


Depending on the condition in question, other symptoms may be associated.

In cases of digestive origin, the animal will often also present with loss of appetite, abdominal pain, diarrhea or even vomiting, weight loss and dehydration. The presence of blood can also be found in vomiting.

If the blood comes from the mouth or pharynx, pain may occur, with difficulty feeding. Blood can also be found in the saliva.

In dogs with a bleeding disorder, blood may be seen in places other than the stool: in the urine, in the nasal cavities or under the skin. More insidiously, internal bleeding in a cavity (chest or abdomen) may exist.

In any case, if the blood loss is severe or has lasted for a long time, anemia may be present. This is manifested by weakness and paleness of the mucous membranes.

Diagnosis following blood in the stool

The vet will start by taking your pet’s history and any symptoms you may have seen. If your dog may have been exposed to toxic products, such as rodenticides, it is essential to report it to him.

Then the veterinarian will perform a complete clinical examination to identify the associated clinical signs and symptoms. Depending on these elements, he may perform additional examinations: blood test, x-rays, ultrasound, urine or stool analysis.

Treatment and prognosis

Treatment depends on the diagnosis and the severity of the animal’s condition at the time of consultation, as well as the prognosis.

If the origin is digestive, a drug treatment of the intestinal bandage type is often prescribed in first intention to calm the digestive inflammation often present. Symptomatic treatment is associated according to the signs present: anti-diarrhea and / or anti-vomiting. A dewormer can also be prescribed if necessary.

If the condition of the animal justifies it, hospitalization may be proposed to put the animal on a drip.

Surgical treatment may be necessary to evacuate a foreign body or remove a tumor.

Rodenticide poisoning can be treated effectively with specific treatment, provided this is started quickly.

In any case, if you notice the presence of blood in your dog’s stool, contact your veterinarian without delay. Most of the time, this can be treated effectively with a favorable prognosis, provided the treatment is as early as possible.


Poisonous plants for dogs

Blood in the urine in dogs