Causes, Diagnosis, and Treatment of Blood in Dog Stool


Blood in a dog stool can have multiple causes and is never normal. The most common reasons for a bloody stool are parasites or an intestinal tract problem.  A bloody stool can also be a sign of minor issues such as constipation (when the blood is red and the stool is dry and hard) to chronic conditions such as a bleeding tumor. 

Puppies, in particular, can have a bloody stool when suffering from parasites (worms) and gastrointestinal infections. Related conditions include anemia, sepsis, and dehydration. In puppies, bright red blood is almost always the result of parvovirus enteritis or intestinal parasites.  

The color of the blood is the first indicator of the cause. 

  • Bright red blood (hematochezia) indicates that bleeding is from the color or lower digestive tract. Common causes include toxins, injury or trauma, bacterial or viral infections, hemorrhagic gastroenteritis, colon inflammation, inflammatory bowel disease (IBD), parvovirus, anal sac infection, or cancer (seen in older dogs).
  • Tarry, dark stools (melena) also have about a dozen potential causes. Darker blood indicates that the blood has been swallowed or digested, a symptom related to a problem in the upper digestive tract. Causes include foreign objects, ulcers, tumors, toxins, pancreatitis, and Addison's disease.

Stool color is when compared to normal since the "healthy" color for each dog can vary based on diet.

Treatment involves identifying the underlying cause and using a specific approach such as de-worming for parasites or dietary change to correct any food intolerance or allergy. A small red streak of blood along accompanied by a hard stool is probably due to constipation and is not of immediate concern. If you see a good amount of blood,  visit your vet immediately for a rectal exam to check for anal and rectal tumors or an anal gland abscess. 

When To Contact Your Veterinarian Immediately:

If you see along with blood in the stool:

  • A large amount of blood 
  • If the blood is digested (black and tarry)
  • Diarrhea
  • Blood in the urine
  • Breathing difficulty
  • Lower activity levels
  • Attitude change
  • Appetite loss
  • Vomiting

A veterinarian needs to check for dehydration, coagulapathy, and anemia immediately when a dog pooping blood is suffering from these symptoms. Do not wait until the next morning.

Blood in the stool of this beagle is due to an intestinal obstruction. Symptoms included anorexia, abdominal distension, weight loss and constipation.
Source: Washington State University, Gustavo Luiz G. Almeida, DVM, MSc, MD


One incident with bright red blood in the stool is usually not a cause for great concern. If it is only a few drops of blood, you don’t need to worry.

Repeated episodes could indicate something that needs immediate treatment.

If the blood is only on the outside of the stool, then the bleeding is from the anal canal. It is common for dogs with this condition to try and pass their stools while standing up. The condition can be caused by an obstruction such as an enlarged prostate, a foreign object that your dog ingested, or a fracture of the pelvic bone.

Also, check to see if your dog has eaten anything with red dye. The dye from household products such as lipstick can add a red color to the stool.

In general, a dog pooping blood isn't an emergency unless you see other symptoms such as lethargy (tiredness), pain, or vomiting.


Blood in the stool of dogs can have many causes, including:

Black, Dark Red, or Tarry Stools (melena)

  • Your dog might have eaten something sharp that is cutting him internally, foreign objects
  • Irritable Bowel Disease (IBD)
  • Bleeding Tumor (seen in the mouth, small intestine, or stomach
  • Medication reaction, particularly anti-inflammatories such as aspirin or human medications
  • Kidney Failure
  • Liver disease (canine hepatitis)
  • Addisons disease (and other hormonal disorders)
  • Infections
  • Pancreatitis (pancreatic inflammation)
  • Parasites (whipworm, hookworm)
  • Gastroduodenal Ulcer in the small intestine or stomach
  • A congenital bleeding disorder (von Willebrand disease and others)

Bright Red Blood


You may see anything from a few red drops to a few streaks of blood on your dog’s feces, or you might notice a lot more blood in his stool. The blood may be bright red, or your dog may have black tarry stools as indicated above.

Bright Red Blood in Dog Stool

Red blood indicates a condition called hematochezia, which means bleeding in the lower part of the colon or rectum.  Red blood is referred to as frank blood or digested blood.

    • If the blood is in a few small streaks, combined with a dry hard stool, constipation is the likely the cause.
    • Large streaks could indicate a bleeding  anal or rectal lesions, such as bleeding anal or rectal tumor or anal gland abscess.
    • Bright red blood in the stool combined with bleeding from another part of the body, such as the mouth or nose, could be a coagulation problem, which occurs when a dog ingests rodent poisons.  See a veterinarian immediately.

Black or Tarry Colored Blood

Black, tarry stools indicate bleeding in the upper part of the intestines or stomach.  It is a condition called melena. The black color is caused by older blood from the upper intestinal tract. Darker blood could point to a is a serious condition such as bleeding ulcers, coagulation problems, or tumors.

Diarrhea in Dogs with a Bloody Stool

Diarrhea in dogs with blood creates raspberry-colored diarrhea. 
Because the colon is very vascular, it is common to see mucus and blood in the stool. Other accompanying symptoms that show signs of gastrointestinal distress include:

  • Flatulence
  • Appetite loss
  • Vomiting
  • Lethargy or weakness
  •  Overall discomfort

Many problems can cause dog diarrhea, including:

  • Viruses
  • Stress
  • Intestinal parasites (hookworm, protozoa, giardia)
  • Inflammatory bowel disease
  • Bacterial diseases that can colonize in the gastrointestinal tract (Salmonella, E. coli, Parvovirus)
  • Inflammatory bowel disease (IBD)
  • Intestinal parasites (more commonly seen in young dogs and puppies)
  • Trauma (injury or surgery on the digestive tract)
  • Toxins
  • Straining during defecation
  • Eating garbage or something that impacts digestion
  • Ulcers
  • Foreign bodies
  • Hemorrhagic gastroenteritis (HGE), a condition often seen in toy-breeds such as Pugs and Pomeranians. If you have a toy breed contact your veterinarian immediately.

Puppies with a Bloody Stool

Blood in a puppy stool is commonly caused by gastrointestinal infections and parasites (worms) and less often from parvovirus. These conditions can result in either a hard or loose stool or diarrhea. Other symptoms can include sepsis (bacteria in puppy blood), dehydration, and anemia. If the blood is red (hematochezia), and the amount is small, then it could be due to a simple case of constipation.  If a large amount of blood is seen, then the problem, in most cases, is parasites or parvovirus.

If parasites cause the stool problem, it is probably due to roundworms, coccidia, or hookworms. Hookworms and roundworms result in puppy blood in a loose stool or diarrhea. Coccidia causes symptoms such as blood in diarrhea, mucus, or diarrhea alone. At the first signs of blood, be sure to see a veterinarian so that treatment can be started early.  It is common to test the feces for the presence of worm eggs. Since eggs may not be shed all of the time, repeated tests may be needed before there is a worms diagnosis.  If puppy worms are the problem, a dewormer will be prescribed by the veterinarian.  Parvovirus cannot be directly cured and is treated by addressing symptoms such as dehydration.


When you go to the veterinarian, take a dog's stool sample with you. This will help your vet to make a diagnosis. The vet can test the stool for parasites and for certain viruses. Also, write down and bring any notes regarding changes in your dog's behavior or eating habits.

Your vet will do a thorough physical exam, checking for things like an anal sac infection, as well as check the rectum for conditions such as an anal gland abscess or rectal and anal tumors. 

If there is a large amount of blood, or if the blood is black and tarry/digested, your vet will probably also do a blood test to check for blood clotting disorders such as anemia, coagulopathy and dehydration. Depending on what he or she finds, the vet may also order x-rays.  

Examination of the feces can indicate parasites, bacteria or to find blood that might not be visible to the naked eye.

A common diagnosis for young puppies is parasites. Cancer is a more common diagnosis for older dogs.

For puppies who have not been vaccinated, parvovirus is a possibility. We strongly encourage you to get your puppy vaccinated, because parvo can be fatal to puppies.


The appropriate treatment depends on the underlying cause. In the case of parasites, medication such as a dewormer is generally prescribed. Antibiotics are given for anal sac infection. Cancer treatment depends on how advanced the disease is and how aggressively the owner wishes to treat it.

If the causes is from eating bad food or something from the garbage, then a short term dietary change can correct the problem. To calm the gastrointestinal tract, dietary change may be recommended to a high fiber or hypoallergenic diet. Intolerance might be treated with an elimination diet (where the diet is limited to chicken and rice and then expanded).

There is no treatment for parvovirus and instead supportive care is given. 

If a foreign object is causing the problem, emergency surgery may be required to correct the issue.


To prevent future problems, we suggest that you not feed your dog bones, because your dog can chew them into sharp pieces that can cut him internally and may cause bleeding.  For overall digestive support after recovery, a natural remedy such as Digestive Support may be of some value in maintaining digestive health.

Have A Question For Our Vet about Dog Blood in Diarrhea or Stool?

Do you have a question for our Vet or a Helpful Story to Share about finding blood in dog stool or diarrhea? Please include information such as age, sex, breed, medical history, symptoms and medications. Also let us know the color of any blood (bright red, dark), consistency of the stool (hard, dry, watery, diarrhea).

We will do our best to get back to you quickly (depends on how many questions we receive each day). If you do require an immediate response we suggest using this online dog veterinary service that is available now.

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What does it mean when a dog has blood in their stool?

The cause of blood in a dog stool can be something that quickly passes or it can be an indicator of a problem that needs to be immediately addressed by a veterinarian. If a few drops or thin streak of blood is seen with no other symptoms, contact your veterinarian the next day if the condition does not go away on its' own. If the blood a large streak, and is accompanied by other symptoms such as vomiting or lethargy, contact your veterinarian immediately.

Is bloody diarrhea in dogs an emergency?

Blood diarrhea could potentially be an emergency if accompanied by other symptoms such as appetite loss, pain, fever or vomiting. Conditions such as acute hemorrhagic diarrhea syndrome (HGE) in dogs is characterized by a sudden onset of bloody diarrhea with or without vomiting in a dog that was previously healthy. Given the potential severity of this condition, contact your veterinarian immediately. In most cases the veterinarian will recommend a dietary change.

What can I give my dog for bloody diarrhea?

Speak to your veterinarian first since diarrhea mixed with blood could be the result of a serious or life-threatening illness. Signs of a more serious illness are often accompanied by other signs such as appetite loss, dehydration, abdominal pain, vomiting, fever or lethargy/weakness. If the diarrhea and blood combination is caused by anal fissures, it could possibly be treated with a fiber rich diet such as vegetables and whole grains. 

Should I take my dog to the vet for bloody diarrhea?

If the bloody diarrhea is accompanied by other signs such as a loss of appetite, weakness, or vomiting, you should absolutely call and possibly visit your veterinarian immediately. 


1. Ruotsalo, Kristiina, and Margo Tant. Fecal Occult BloodVCA Animal Hospitals.