What Dog Diarrhea Blood Means for Your Pup's Health Gastrointestinal Issues at Their Worst

What Dog Diarrhea Blood Means for Your Pup's Health
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If you find blood in your dog's diarrhea, it may be time to sound the alarm. Find out here some common reasons why blood might be showing up in your dog's stool, and if you'll have to see the vet.

Periodic diarrhea is a common problem for dogs, but if you notice that it looks bloody or tar-like, you should treat it as an emergency. Thanks to their extensive and varied diet, dogs are prone to gastrointestinal issues, but the types that cause bleeding are often more dangerous and a cause for serious concern. Here’s what to do if your dog has diarrhea with blood in it.


When you notice blood in diarrhea, it means that somewhere during digestion, an ulcer or other injury has caused bleeding. If this bleeding is in the stomach or small intestine, it is more likely to look like tar and have a strange odor due to partial digestion. If bleeding occurs later in the process, in the colon or rectum, you are more likely to see bright red blood.

In addition to blood in diarrhea, you may also notice that your dog is acting tired, showing a loss of appetite, vomiting, or having a fever. Only a veterinarian can determine what may have caused the bleeding through a physical and tests, so it's important to consult immediately. Depending upon the symptoms, your vet may suggest immediate treatment or hospitalization.

Possible Causes of Bloody Dog Diarrhea

Ulcers and Colitis

While we may be more familiar with ulcers in the stomach, they can occur at any point along the digestive process and often lead to blood in diarrhea.


Several viruses attack the gastrointestinal tracts of dogs, including the parvovirus and coronavirus, and this damage often leads to bleeding. “Parvo” is highly contagious and can be fatal, so it’s critical to act fast. Vaccinating new puppies can help your dog avoid the worst of these viruses.


Bacteria may be the most common cause of blood in diarrhea, often inflaming tissues after growing in the intestines. Several common bacteria that affect dogs include salmonella, e-coli, and campylobacter. These can also infect humans and lead to similar results.


Worms and protozoa can wreak havoc on the gastrointestinal tract and make it difficult for your dog to absorb nutrients. Some common types include whipworms, hookworms, and Giardia, which may enter while eating rotten food or drinking contaminated water.


Sometimes dogs eat plants they shouldn't or can get into poisons intended for rats and other pests. Warfarin (rat poison toxin) or other poisonous mixtures can lead to blood in your dog’s stool. Keep household chemicals and rodent-killing poisons locked up or out of your dog’s reach.


Unfortunately, blood in diarrhea may also be a sign of gastrointestinal cancer, which may have already caused substantial damage.

Other conditions

Many other illnesses can lead to bloody diarrhea, such as liver or kidney failure, Addison’s disease, blood-clotting issues, or hemorrhagic gastroenteritis (HGE), which often causes sudden, heavy bleeding and requires immediate veterinary attention.


Your vet will determine treatment once they diagnose the cause of the bleeding. Many conditions will require medications or even surgery. Usually, dogs should not be fed for 12 to 24 hours after diarrhea, and in some extreme cases, water will even be withheld (paired with intravenous fluid) to let the intestines recover. In all other cases, providing your dog with unlimited water will be crucial to avoid dehydration and septic shock.

Noticing these symptoms early and contacting your vet is key to successful recovery. If treated early, dogs usually respond well to medications treating parasites or bacteria, though some illnesses, such as cancer, may be more challenging to treat.

Why does my puppy have blood in her diarrhea?

Acute diarrhea in dogs is a common issue, and most cases require no treatment beyond addressing dehydration. However, bloody diarrhea is an indication that the condition is severe and may warrant diagnostic and therapeutic interventions. The possible causes may vary from intestinal parasites to infections, problems with the anal glands, and ingestion of toxins or foreign bodies. Furthermore, injuries and medical conditions may cause your dog to have blood in its stool. The concern gets bigger if a puppy suffers from the condition. Paul Mitchell, BSc BVMS in Veterinary Science & Veterinary Medicine, notes that you must visit a vet sooner rather than later to get a diagnosis. Ulcerative colitis is relatively common in canines, but there is also a rare chance of colonic or rectal tumors leading to the condition. 

Is bloody diarrhea in dogs curable?

In most cases, bloody diarrhea in canines is highly treatable, provided you seek medical attention on time and take the recommended precautions. However, the cause of the illness determines the prognosis. Your vet may recommend medications to ease the diarrhea and address the underlying cause. They may also prescribe probiotics and prescription diets to help the dog to heal. If the condition is caused by a tumor or foreign object obstruction, they may suggest surgical intervention. Fluid and blood transfusions may be needed to address dehydration or anemia. Once the underlying issue is treated, give your dog’s inflamed intestines enough time to rest and heal. In the long run, you may have to change your pet’s diet to alter fiber intake or reduce inflammation. 

How long can a dog survive with bloody diarrhea?

Research shows that most dogs with bloody diarrhea survive, but the mortality rate runs high if acute hemorrhagic diarrhea syndrome (AHDS) is untreated. Nearly 10-15% of dogs encounter repeat occurrences of AHDS, but 28% eventually develop chronic signs of GI disease down the road. Fortunately, your dog may need only a few days to make a full recovery if treated promptly and appropriately. Michael Hoover, a veterinarian, states that the condition must be properly diagnosed first, whether it is caused by colitis, parvovirus, pancreatitis, or lymphocytic/plasmacytic gastroenteritis. Without proper diagnosis and treatment, your dog may become dehydrated, resulting in severe illness and even death.

Can I treat my dog’s bloody stool at home?

This depends on the underlying cause of bloody stool. In many cases, hemorrhagic colitis, a large bowel inflammatory condition, causes bloody stool in dogs. The condition requires fasting for 24 hours to resolve naturally. You can follow the fasting period by feeding your pet meat broth or cooked squash with vegetables. Additionally, high-quality dog-specific probiotics can accelerate the healing process, but you must start them only after a vet visit. A probiotic supplement is made with a blend of good bacteria that support digestive function, strengthen the dog’s gut, and help restore the microbiome balance. While these remedies work for a dog suffering from hemorrhagic colitis, it will not help if bloody diarrhea is attributed to an infection or tumor. Your pet will require medical or surgical intervention in these cases. 

Can changing dog food cause bloody diarrhea?

When it comes to the causes of bloody diarrhea in dogs, they may not always be related to underlying medical issues. At times, new dog food may cause stomach upset, resulting in bloody diarrhea. According to Bob Dehler, a veterinarian, enzyme production begins in a dog’s body when it is given something new to digest. It may take days to reach a sufficient enzyme level for good digestion. Meanwhile, the stuff stays in the intestines in different stages of digestion, causing loose stools. Blood may also appear in stool during the transition. Going slow with the change in your pet’s diet is the best way to prevent it. Start with small quantities or one meal, and gradually increase the intake once your pet becomes habitual to the new product and does not show any adverse reactions. 

Can worms cause bloody diarrhea in dogs?

Yes, intestinal worms can cause a variety of digestion-related symptoms in dogs and puppies. These include loose stools, bloody diarrhea, dehydration, vomiting, loss of appetite, lethargy, and weight loss. Roundworms are the most common parasite found in canine intestines. Other potential culprits are hookworms, tapeworms, whipworms, and giardia. Since these pests thrive in the environment, you must do your bit to protect your canine companion from them. A clean environment, regular monitoring, and deworming treatment can prevent worm infestation in pets. 

More on Gastrointestinal Problems

What Causes Gastritis in Dogs and Cats?
Is Your Dog Puking Blood? Here's What You Do
How To Change Dog Food

This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.

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