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Gastroenteritis in Dogs

What Is Gastroenteritis in Dogs?

Gastroenteritis in dogs refers to the inflammation of a dog’s stomach (gastro-) and small intestine (-enteritis). Essentially, it’s akin to an upset stomach in dogs. While some pet owners may colloquially refer to it as a “dog stomach bug,” the causes of gastroenteritis extend beyond just viral infections.

If your dog experiences bloody diarrhea or vomiting, it’s crucial to seek immediate attention from the emergency vet, as these symptoms could indicate acute hemorrhagic diarrhea syndrome (AHDS).

Acute Hemorrhagic Diarrhea Syndrome (AHDS) / Hemorrhagic Gastroenteritis (HGE)

Acute Hemorrhagic Diarrhea Syndrome (AHDS), also recognized as Hemorrhagic Gastroenteritis (HGE), represents a specific and severe form of enteritis, marking a medical emergency and among the most severe causes of diarrhea in dogs.

AHDS poses a fatal threat; your dog could fall into septic conditions due to a perilous bloodstream infection, experience significant protein loss, or encounter complications. Dogs afflicted by this condition demonstrate inflammation solely within the intestines, not the stomach. If you suspect AHDS in your dog, promptly seek veterinary assistance.


If you notice the signs of AHDS in your dog, it’s crucial to take them to the emergency vet immediately:

  • Sudden onset of bloody diarrhea without any known cause, such as a dietary change
  • Vomiting, with or without the presence of blood
  • Lethargy (slow movement, sluggishness)

Contact your vet if your dog displays any indications of gastroenteritis:

  • Sudden vomiting
  • Sudden onset of diarrhea
  • Lethargy

Dogs experiencing gastroenteritis typically exhibit sudden vomiting and/or diarrhea, potentially leading to significant loss of body fluids and electrolytes, resulting in dehydration. It’s important to monitor your dog’s hydration and activity level closely.

If your dog appears dehydrated and/or lethargic, seek immediate assistance from the emergency vet, as it indicates a more severe condition requiring urgent treatment.

You can assess for dehydration by gently lifting the skin on the back of your dog’s neck. If it remains raised and doesn’t return to its original position promptly, your dog is likely dehydrated.

Another method to test for dehydration in your dog is by pressing on their gums, which should regain their pink color within 2 seconds. If it takes longer for the pink color to return, your dog is likely dehydrated.

Additional signs of dehydration include:

  • Excessive panting
  • Dry nose and eyes
  • Dry, sticky gums, and thick saliva
  • Loss of appetite
  • Reduced skin elasticity (when you pull your dog’s skin and it is slow to bounce back)


Gastroenteritis in dogs can stem from various underlying issues. Your veterinarian can conduct diagnostic tests to help identify the root cause of your dog’s illness. Some potential causes include:

  • Dietary indiscretion, where your dog consumes inappropriate items like fatty foods, spoiled food, or non-edible objects
  • Gastric ulcers
  • Exposure to toxins
  • Cancer
  • Kidney failure
  • Liver failure
  • Bacterial infections such as Clostridium, Campylobacter, Salmonella, or E. coli
  • Viral infections like parvovirus, coronavirus, or distemper
  • Parasitic infestations
  • Food allergies

The precise cause of AHDS remains elusive. Some veterinarians speculate that the condition initiates with a bacterial infection in the intestine triggered by Clostridium perfringens type A. This infection generates harmful toxins that degrade the protective lining of the intestine, leading to leakage of fluids and blood.


The diagnosis of gastroenteritis in dogs typically occurs when a dog experiences sudden vomiting or diarrhea, accompanied by lethargy, sluggishness, and a loss of appetite. Providing detailed descriptions of your dog’s symptoms aids the veterinarian in making an accurate diagnosis. Additionally, your vet will assess your dog for signs of dehydration and abdominal discomfort.

In order to eliminate other potential causes of vomiting and diarrhea, such as parvovirus, parasites, gastrointestinal blockages, cancer, kidney disease, and other serious conditions, your veterinarian may require a fecal analysis, blood tests, X-rays, or ultrasound scans.

Diagnosis for AHDS in Dogs

Your veterinarian will also consider AHDS as a potential cause if your dog presents with symptoms such as bloody, watery diarrhea, dehydration, and an elevated packed cell volume (indicating the number of red blood cells currently in circulation).

There isn’t a specific test available to diagnose AHDS in dogs. If no other underlying cause is identified for your dog’s symptoms, a diagnosis of AHDS might be established through a process known as “diagnosis of exclusion.”

It’s important to note that an Addisonian crisis, characterized by acute gastrointestinal symptoms often accompanied by bloody diarrhea in dogs with Addison’s disease, can closely resemble AHDS. An untreated Addisonian crisis can be fatal. Given the severity of both an Addisonian crisis and AHDS, it’s imperative to seek veterinary care immediately if your dog shows signs of dehydration or presents with bloody diarrhea.


The primary aim of treatment is to cease vomiting/diarrhea and uphold hydration levels. Based on your dog’s condition and the root cause, your veterinarian may prescribe anti-vomiting medication, antibiotics, and antacids tailored for dogs.

In cases of vomiting, the medications will be administered via injection. Hospitalization may be necessary for your dog to receive IV (intravenous) fluids and electrolytes.

Treatment for AHDS in Dogs

AHDS demands urgent attention and cannot be managed at home. If your dog exhibits bloody diarrhea or vomiting, it’s imperative to seek immediate assistance from the emergency vet.

Dogs afflicted by AHDS are experiencing a perilous loss of fluid, protein, and electrolytes, necessitating hospitalization for intensive IV therapy, electrolyte supplementation, and medication.

In cases of AHDS, the survival rate reaches 90–95% if prompt, aggressive treatment is initiated. Typically, most dogs recover within two or three days.

Living and Management

Upon returning home from the vet, you can continue providing care for your dog. If the vet determines that your dog’s gastroenteritis stems from something contagious, it’s essential to isolate your dog from other pets. Refrain from allowing your dog to eat or drink until there has been no vomiting for six to eight hours.

Subsequently, you can offer your dog small quantities of clear liquids such as water, Gatorade, Pedialyte, or other electrolyte solutions every two hours.

If your dog manages to keep down the fluids after 12 hours, gradually introduce frequent, small meals of boiled hamburger and rice or boiled chicken and rice, serving about ¼ cup or less per feeding.

Recovery From AHDS in Dogs

As part of your dog’s recovery regimen from AHDS, it’s important to incorporate a bland diet that is rich in carbohydrates and low in protein and fat. Your veterinarian might provide special canned food options, or you can prepare meals at home for your dog.

Options such as cooked rice or pasta, potatoes with a bit of cottage cheese, lean boiled ground beef, or skinless chicken are suitable choices for a few weeks while your dog’s gastrointestinal system heals and their appetite improves. Consult your veterinarian to explore cooking options for your dog, ensuring that you provide the necessary nutrients in appropriate quantities.

Gastroenteritis in Dogs FAQs

How can I manage my dog’s gastroenteritis at home?

If your dog experiences vomiting or diarrhea, it’s essential to contact your veterinarian promptly. They will inquire about specific details to gauge the severity of the situation. If your dog displays lethargy or shows signs of blood in their vomit or diarrhea, immediate veterinary attention is necessary. Dogs with AHDS require hospitalization and cannot be treated safely at home.

Following a thorough assessment of your dog’s symptoms, your veterinarian may deem it safe for home management and provide you with a tailored treatment plan. This may involve administering small amounts of clear liquids (water, Gatorade, Pedialyte, or other electrolyte solutions) every 2 hours, but only after vomiting ceases for 6 to 8 hours.

If your dog successfully retains the fluids after 12 hours, offer frequent, small meals of boiled hamburger and rice or boiled chicken and rice, serving about ¼ cup or less per feeding. Avoid administering over-the-counter or prescription medications without consulting your veterinarian first.

Can gastroenteritis be fatal for dogs?

Yes, gastroenteritis can progress to acute hemorrhagic diarrhea syndrome (AHDS) if left untreated. AHDS represents the most severe form of gastroenteritis in dogs and can result in life-threatening dehydration if not promptly addressed.

Is gastroenteritis transmissible from dogs to humans?

Some causes of gastroenteritis are zoonotic, indicating they can transmit from dogs to humans. Bacterial infections like E. coli, salmonella, and listeria fall into this category.

However, certain causes are specific to dogs and pose no harm to humans, such as canine parvovirus and distemper.

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