Hemorrhagic Gastroenteritis In Dogs

Amanda Sarvas

If your dog suddenly starts vomiting and has lots of bloody diarrhea, it may be hemorrhagic gastroenteritis in dogs. This condition is a medical emergency, and your dog should see a veterinarian as soon as possible. 

What Is Hemorrhagic Gastroenteritis In Dogs?

Hemorrhage is the medical term for bleeding. Gastroenteritis is inflammation of the gastrointestinal (GI) tract. The symptoms include vomiting and diarrhea. So hemorrhagic gastroenteritis (HGE) is when sudden bloody diarrhea occurs.

HGE typically comes on very quickly with no warning signs. It often happens in healthy dogs with no known predispositions. 

Acute Hemorrhagic Diarrhea Syndrome 

Hemorrhagic Gastroenteritis is also sometimes called acute hemorrhagic diarrhea syndrome (AHDS).  You may see these terms used interchangeably. 

Symptoms of Hemorrhagic Gastroenteritis in Dogs

Hemorrhagic Gastroenteritis can progress quickly and can be fatal if left untreated. Don’t hesitate to take your dog  to your veterinarian if you suspect this condition. 

There are few to no warning signs before HGE develops, but here are some symptoms you might see … 

  • Bloody diarrhea that looks similar to raspberry jam
  • Vomiting
  • Dehydration 
  • Anorexia
  • Lethargy
  • Abdominal pain (1). 

Most dogs with HGE won’t run a fever. 

How Vets Diagnose Hemorrhagic Gastroenteritis

The diagnosis of HGE is based on symptoms. Your vet will first rule out other causes of bloody diarrhea. These include intestinal parasites, parvovirus, and bacterial infections. Your vet will usually run a series of blood tests. 

Dogs with hemorrhagic gastroenteritis have a packed cell volume of at least 60%. A packed cell volume is a blood test that measures how many red blood cells your dog has. A normal red blood cell count is 30-50%. A higher packed cell volume can be a sign that your dog is extremely dehydrated (2). 

Which Dogs Are Most At Risk for Hemorrhagic Gastroenteritis? 

Dogs of any age, size or breed can get HGE.  But it seems to happen most commonly in young dogs (the median age is 5 years old). 

Small and toy breeds are also at a much higher risk and are overrepresented in HGE cases. The following breeds are more likely to get hemorrhagic gastroenteritis: 

  • Yorkshire Terrier
  • Miniature Pinscher
  • Miniature Schnauzer
  • Miniature Poodle
  • Maltese

Causes Of Hemorrhagic Gastroenteritis 

Hemorrhagic gastroenteritis is still very much a mystery to the veterinary medical world. The cause is unknown, and so there is no recommendation for prevention. There are many theories about what causes hemorrhagic gastroenteritis, including parasites, bacterial infections, food allergies, pancreatitis, anxiety, and stress. 

HGE does not appear to be contagious between dogs, although dogs living together can sometimes develop the condition at the same time. This supports the idea that something in the environment could be causing it. 

One theory is that hemorrhagic gastroenteritis may be caused by an infection with or hypersensitivity to the bacteria Clostridium perfringens. Clostridium bacteria have been found in the small intestines of dogs who have HGE. This suggests there may be a relationship between Clostridium and hemorrhagic gastroenteritis (1). 

It’s important to know that you cannot avoid this bacteria as a prevention for hemorrhagic gastroenteritis. Research states … “Clostridium perfringens is present throughout the environment, including soil, sewage, feces, foods, and the normal gastrointestinal flora of animals (3).” 

Boosting your dog’s gut health with good bacteria can help crowd out bad bacteria, so you may want to consider giving a high quality daily probiotic. 

There is also an interesting correlation between acute pancreatitis, clostridium bacteria, and hemorrhagic gastroenteritis. Pancreatitis disrupts the production of trypsin, an enzyme produced in the pancreas. Trypsin would normally destroy the toxins produced by the Clostridium perfringens bacteria in the small intestines. Without trypsin, the Clostridium bacteria can release a multitude of toxins which can then lead to hemorrhagic gastroenteritis and even intestinal tissue death. Small dogs are more likely to have pancreatitis than large dogs. So this may also help explain why small dogs are more prone to HGE (4).  

Treatment For Hemorrhagic Gastroenteritis 

As warned earlier, HGE can be a medical emergency so it’s important to recognize the signs and see your veterinarian right away if you suspect it in your dog. 

Not all dogs need intensive treatment and IV fluids. Even for those who do, the outcome is usually positive. If your dog has a more severe case or is in a higher risk category (small breed, young or senior), it’s essential to get to your vet quickly.  Dogs may not be dehydrated when they’re first examined, but it can progress quickly. 

Extreme dehydration can lead to: 

  • Low blood pressure
  • Increased red blood cell count
  • Blood clotting issues
  • Shock
  • Kidney failure
  • Death 

Your vet will likely start your dog on IV fluid immediately to prevent dehydration. She may also recommend antibiotics to deal with any bacterial infections, although their efficacy for HGE is questionable (1). 

After consulting with your veterinarian, you may be able to bring your dog home to monitor him at home. Consider giving a home-made bone broth to help keep him hydrated, and give gut soothing herbs like slippery elm or marshmallow root. 


  1. Gallagher, A. Acute hemorrhagic diarrhea syndrome in dogs - digestive system. Merck Veterinary Manual. 2022 Oct 18.
  2. Trotman, Tara K.  VMD, DACVIM. Hemorrhagic Gastroenteritis. Small Animal Critical Care Medicine (Second Edition), 2015. 
  3. Li J, et al. Clostridium perfringens Sialidases: Potential Contributors to Intestinal Pathogenesis and Therapeutic Targets. Toxins (Basel). 2016 Nov 19;8(11):341.
  4. Gohari IM, et al. A Novel Pore-Forming Toxin in Type A Clostridium perfringens Is Associated with Both Fatal Canine Hemorrhagic Gastroenteritis and Fatal Foal Necrotizing Enterocolitis. PLOS ONE. 2015 Apr10(4): e0122684.
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