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Blood in Dog Stool: What It Means and What to Do

Blood in dog stool can mean a number of things — some require urgent attention, and some do not. If you spot this, tell your veterinarian right away.

Blood in Dog Stool: What It Means and What to Do

Blood in dog stool can mean a number of things — some require urgent attention, and some do not. If you spot this, tell your veterinarian right away.

When a dog owner sees blood in their dog's poop, it's easy to assume the worst and panic. But the truth is that blood in dog stool can occur for a variety of reasons. Some of them are serious, and some of them are less worrisome. 

Of course, any kind of blood in stool means something is wrong. That's why it's a good idea to keep a close eye on your dog's bowel movements — gross, we know — and monitor the color and consistency of Fido's fecal matter. 

This way, if you notice possible blood in your dog's stool, you can take quick action and let your veterinarian know. That's the quickest way to get your dog help. 

Let's take a closer look at the different types of bloody stool, the possible causes of blood in dog stool, and what to do if you notice your dog pooping blood.

Types of Bloody Diarrhea

Blood in dog stool will generally appear in one of two ways: In the form of dark, black, tarry stools, or as bright red blood.


When blood comes from the upper digestive tract (the small intestine and the stomach), it will appear as dark red, black, and tarry. It's dark because the blood has gone through the digestive process. This is known as melena. 

Conditions that affect the upper digestive tract like inflammatory bowel disease or stomach ulcers could result in melena. Note that your dog's poop will typically be more solid when melena is present instead of runny or watery diarrhea. 


Hematochezia indicates bright red blood in dog stool. This blood is coming from the lower digestive tract (the colon and anus), and it's bright red because it has not gone through the digestive process. 

Hematochezia usually accompanies diarrhea instead of solid bowel movements. You may also notice mucus on the outside of the stool. Dogs demonstrating hematochezia might also poop more frequently and in larger volumes. Conditions like bacterial infections, viral infections, or hemorrhoids could be to blame. 

Why Is There Blood in My Dog's Stool?

blood in dog stool: dog laying on the couch

Bloody stool or bloody diarrhea can be a symptom of many health conditions, some of which have been mentioned above. If you're asking yourself, "Why is there blood in my dog's stool?" one of the following causes might be to blame. 


Did you know that dogs can get hemorrhoids, just like humans? Hemorrhoids or irritation of some kind near the rectum is another common cause of blood in dog stool. You'll probably see bright red blood on the outside of Fido's stools if this is the case. 

Anal Gland Issues

Your dog has two small sacs, one on either side of their anus, that release drops of scent when your dog releases a bowel movement. These are the anal glands. They can become enlarged, impacted, inflamed, and infected, which can often lead to a bit of bright red blood in the stool. 

Foreign Body Ingestion

We've learned that blood in the stool often relates to something that affects the gastrointestinal tract, which includes the stomach, small intestine, colon, and anal area. And one of the most common things that affects the GI tract is ingestion of a foreign body.

As you know, dogs often like to eat things they shouldn't, from bones and socks to rocks and garbage. These items can inflame the digestive tract or even pierce the intestinal lining, resulting in bloody bowel movements.

Inflammatory Bowel Disease

Inflammatory bowel disease is another illness that can cause blood to appear in dog stool. IBD is a chronic disease of the intestinal tract characterized by repeated or consistent inflammation in the digestive tract. In the early stages of IBD, you'll probably see bright red blood. In later stages, you'll likely see dark red or black blood.

Illness and Infection

A wide range of illnesses and infections can lead to blood in dog stool. Examples include:

  • Bacterial and viral infections like parvovirus
  • Parasitic infestations from hookworms, roundworms, giardia, and others
  • Pancreatitis
  • Hemorrhagic gastroenteritis (HGE), an intestinal condition of unknown cause characterized by acute bloody diarrhea and vomiting. It occurs most often in young to middle-aged small-breed dogs like Miniature Schnauzers, Yorkshire Terriers, and Miniature Pinschers. 
  • Other digestive system issues like colitis or intestinal ulcers


A dog that has ingested a toxic substance of some kind may exhibit bloody stools or bloody diarrhea as a symptom. Examples of toxins include antifreeze, rat poison, and toxic foods like grapes or onions, among others. This is a medical emergency, so you should rush your dog to the vet’s office right away if you know or suspect they’ve ingested a toxin.

Kidney Failure

Another condition that can cause dark black blood to appear in your dog's stool is kidney failure, known medically as renal failure. Other symptoms are sure to appear alongside the bloody stool, such as vomiting, lethargy, pale gums, uncoordinated movements, loss of appetite, and weight loss. If your pet is exhibiting any of these symptoms, rush them to the veterinarian’s office for immediate treatment.


Yes, cancer is another possible cause of dark or black bloody stool, especially if tumors are located in the digestive tract. But while it's important to be cautious, try not to jump to conclusions until you’ve talked with your vet. Digestive tumors are a far less common cause of blood in dog stool than the other conditions on this list. 

What Should I Do If I Spot Blood in Dog Stool?

dog laying on the bed

As soon as you spot blood in your dog's stool, whether it's dark and tarry stools (melena) or bright red blood (hematochezia), tell your veterinarian. Quick diagnosis and treatment is the best way to get your dog back to full health. 

A wide variety of tests might be performed by your veterinarian to determine the cause of the bloody stool. X-rays and ultrasound scans, blood work, and testing of stool samples are common. 

If your vet determines that your dog's condition is life-threatening (if kidney failure is present or if your dog has ingested a toxin, for example), they may refer you to an emergency vet or take your dog into the intensive care unit or the emergency room for immediate care. 

The exact treatment will, of course, depend on the underlying cause. Surgery may be needed to remove a foreign object. Bacterial infections and parasitic infestations will be treated with antibiotics and anti-parasitic medications. Anal glands may need to be expressed, and antibiotics can help if they've become infected. In the case of a viral infection like parvovirus, supportive care will be given while the disease runs its course.

As your dog recovers from their condition, your dog may need to eat a bland diet as their gastrointestinal system recovers. This usually consists of plain dishes like white rice and unseasoned, boiled chicken. Your veterinarian can advise you further. 

In addition to eating a healthy diet, your dog may benefit from taking a probiotic supplement. Probiotics help to support a thriving gut environment and can help with digestive issues. Native Pet's all-natural probiotic powder is a great option.

How Should I Respond to Blood in My Dog's Stool?

Blood in dog stool will appear in one of two ways: As bright red blood, or as dark red to black blood in tarry stools. Bright red blood indicates an issue in the lower digestive tract, while dark blood means something is happening in Fido's upper digestive tract. 

No matter what kind of blood you spot in your dog's bowel movements, let your vet know as soon as possible. Left untreated, the conditions that cause blood in your dog's poop can result in serious health problems. You'll want to have your pet examined as soon as possible.

If you would like more great articles on your dog's health and wellness, check out the Native Pet blog

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