What is hemorrhagic gastroenteritis in dogs?

Hemorrhagic gastroenteritis in dogs occurs when large amounts of fluid seeps into the gut. It’s not known precisely what causes all cases of HGE in dogs, but it can lead to severe vomiting and bloody diarrhoea in dogs. Sometimes the diarrhoea contains so much blood it resembles raspberry jam. While HGE can be seen in dogs of all ages and breeds, it most commonly affects small and toy dogs, particularly miniature pinschers, miniature Schnauzers, miniature poodles, Maltese and Yorkshire terriers. The average age of dogs diagnosed with HGE is five, and most cases occur without warning.

What to do if your dog is showing signs of HGE?

HGE is a life-threatening condition. Untreated, it can quickly lead to hypoglycemia, which is low blood sugar, or hypovolemic shock, which occurs when a dog’s blood or fluid levels drop dramatically. You should contact your vet straight away if your dog or puppy is showing signs of the disease as it can be fatal.

An image of a brown dog laying down on the floor looking sad for Vets Now article on dog gastroenteritis
Hemorrhagic gastroenteritis in dogs is a life-threatening condition. Untreated, it can quickly progress to hypoglycemia.

What causes hemorrhagic gastroenteritis in dogs?

The cause of HGE in dogs has been the subject of vigorous debate and research, but it remains unknown. Theories have ranged from allergic reactions to food, parasites and toxins to bacterial infections. It often affects dogs who are highly strung, so stress, anxiety and hyperactivity have been cited as possible contributing factors.

How is HGE in dogs diagnosed?

Your vet should be able to give you a diagnosis based on your dog’s symptoms and the results of a blood test. Dogs with hemorrhagic gastroenteritis usually have a higher than normal packed cell volume (PCV), which is a measurement of the proportion of red blood cells in their bloodstream. It’s likely your vet will also take steps to rule out other causes of gastrointestinal issues and blood in the stools such as parvovirus, Addison’s disease, intestinal parasites and rat poison intoxication. This may involve carrying out additional tests including x-rays, ultrasound, a biochemistry panel and taking urine and faecal samples.


Hemoconcentration is one of the most dependable findings in dogs with HGE. It occurs when there is a very high percentage volume of red blood cells compared to fluid volume of blood. It’s usually caused by a dramatic loss of water and electrolytes such as sodium, potassium and chloride.

Why is my dog not eating after HGE?

Dogs with HGE will often appear severely ill and, in most cases, won’t regain their appetite for at least a few days. It’s unlikely your vet will feed your dog during the first 24 hours of treatment. After that, once their condition has started to improve and they’re no longer being sick, water and small, bland meals can be offered.

An image of a dog looking unwell for Vets Now article on gastro in dogs, answering the question 'my dog is pooping blood and diarrhea?'
Hemorrhagic gastroenteritis in dogs occurs when large amounts of fluid seeps into the gut.

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Treating HGE in dogs

As HGE can result in severe dehydration, aggressive intravenous fluid therapy (putting a dog on a drip) is usually the mainstay of treatment. Anti-nausea and anti-diarrhoea medication may also be administered if your dog is repeatedly sick while antibiotics are prescribed if there’s evidence of bacterial infection. In the most severe cases, plasma may be needed to correct low blood protein levels.

HGE survival rate

The prognosis for HGE in dogs is generally good as long as treatment is early, appropriate and aggressive. In most cases, dogs with HGE will need to be hospitalised for at least 24 hours. It’s estimated fewer than 10% of dogs who are treated for HGE will die. However, there is a 10 to 15% chance of the condition recurring. The outlook may be worse for very young dogs, or those with other illnesses.

Prevention of HGE in dogs

Prevention advice is based mainly on common sense. For example, owners should try to ensure their dogs live in a low-stress environment, are fed a high-quality balanced diet and given parasite preventive medications as directed by their daytime vet.