Gastroenteritis in Dogs: What You Need to Know

How long does gastroenteritis last in dogs?

This is a difficult question to answer because it depends on the cause and whether the signs are acute or chronic. Most cases of acute gastroenteritis will resolve with time and some supportive care at home. These cases typically last 24–48 hours, the same as when humans get a stomach bug. 

If your dog is vomiting or has diarrhoea, the first thing to do is make sure they stay hydrated. Vomiting in particular can lead to rapid dehydration and loss of essential minerals. Make sure there are plenty of fresh water bowls around, so your dog never has to go far to get a drink. You can also put electrolyte powder in the water to help replace the minerals, but take care that the flavour doesn’t put your dog off drinking.

Don’t withhold food unless they are actively vomiting. Food is essential for recovery and healing of the gastrointestinal tract. Your vet can provide recommendations for special highly digestible foods that are designed for pets with gastrointestinal upset.  While cooked chicken breast and rice has been recommended historically, this isn't balanced and may not provide all of the necessary nutrients.  Speak to your vet clinic as soon as you can to get the right food.

Chronic cases, as mentioned above, may last weeks or months. These always need veterinary attention.

Although acute cases of dog gastroenteritis may resolve on their own, there are some instances where it is essential to see your vet, as gastroenteritis can be life-threatening.

When to Take Your Dog to the Vet

Many dogs with mild acute gastroenteritis will appear surprisingly normal. They may show no signs other than a change in the quality, quantity, frequency or location of their stool. However, if you notice any of the following symptoms, seek veterinary help as quickly as possible. Be extra cautious with puppies, senior dogs and small breeds, as these will become dehydrated and ill much more quickly than larger adult dogs.

When to see a vet:

• Symptoms have lasted more than 48 hours. If your dog is regularly vomiting for more than 24 hours, get help.
• There is blood in the vomit or the diarrhoea. Also watch for ‘coffee grounds’ in the vomit or very dark or black stools. These are potentially more serious signs of intestinal bleeding.
• Your dog seems to be in pain – withdrawn, hunched, whining, adopting the play bow position.
• Your dog is not eating.
• Your dog is depressed or lethargic and reluctant to move.
• Your dog is dehydrated – a good way to test this is with the ‘skin tent test’. Gently pull the skin over your dog’s shoulders up in the air and let go of it. It should snap back into position immediately. If it’s slow to return, your dog is dehydrated. If it stays up, your dog is dangerously in need of intravenous fluids and veterinary help. 
• You think your dog might have eaten something toxic.

How gastroenteritis is managed in dogs

Calling your vet should always be the first step if you suspect an issue with your dog's digestive health. They can let you know the best recommendations for your dog and tell you if your pet needs to be examined straight away. Your veterinarian may need to run tests such as a faecal examination, bloodwork, x-rays, or an ultrasound to determine the cause of your dog’s symptoms. Some cases of gastroenteritis, especially chronic cases, may need feeding trials with a specialised food, biopsies of the gut or exploratory surgery.

Your vet may recommend one or more of the following:

• A dietetic food is typically recommended. This may be for short term recovery, but some dogs may need a diet change for life (see below)
• Medication to control nausea and vomiting
• Anti-parasite medication
• Anti-inflammatory drugs
• Antibiotics (these should only be given if there is a strong suspicion of a severe bacterial disease, as antibiotics can have a devastating effect on the normal microbiome)

The role of nutrition in gastroenteritis

The role nutrition plays in gastroenteritis can't be overstated because good nutrition can benefit the majority of cases. We now know just how important the microbiome is in dogs, humans and many other animals. It affects our immune system and even affects our moods and brain activity. It is a powerful thing that needs nourishment and looking after. 

Gastrointestinal foods fall into a few categories, and which one your dog is recommended will depend on what your vet feels is the underlying cause.

1. Highly digestible foods with lower fibre and a moderate fat level. These foods are used for recovery and up to two weeks of acute gastroenteritis. They are also important for dogs that are vomiting, as high levels of fibre can delay gastric emptying and make vomiting worse. They are also important for underweight dogs that need to maximise the nutrition they get from smaller volumes of food. 
2. Highly digestible foods with low fat levels. These foods are important for dogs with, or prone to, pancreatitis.
3. High-fibre foods with added prebiotic fibres. Most GI diets these days will contain prebiotic fibre, but some foods provide a blend of soluble and insoluble fibre as well as important prebiotic fibre. Prebiotic fibre is indigestible to your dog but it nourishes the ‘good bacteria’. This supports gut health and keeps the ‘bad bacteria’ at bay. These foods can be beneficial for many dogs, especially those with chronic gastrointestinal symptoms. 
4. Foods for dogs with food sensitivities or adverse food reactions (AFRs). AFRs are food allergies and intolerances. The vast majority of AFRs are to protein sources such as beef, dairy and chicken. These specialised foods fall into two categories:
   1. Hydrolysed foods. These are foods in which the protein has been broken down into pieces that are too small for the body to recognise and react to.
   2. Novel protein foods. These are foods that contain a protein source your dog has never had before and would be unlikely to react to. They can consist of things like venison, duck, egg or insect protein.
5. Foods high in crude fibre. These are useful for diabetic dogs, as the high fibre content slows down the release of sugars into the bloodstream and can help stabilise diabetic patients. They are also used to bulk up stools, which can help with anal gland issues and other fibre-responsive problems.

In summary…

Many cases of gastrointestinal symptoms in dogs, both acute and chronic, can be very successfully managed with a change in nutrition or with nutrition and medications. Of course, some causes, like cancer, poisoning or viral diseases, can be very serious and may need additional treatments. If ever you are concerned about your dog’s health, seek veterinary help sooner rather than later, as an early diagnosis is always best to reduce the severity of the symptoms and the problem itself. Together with your vet, you can ensure your dog is feeling tiptop again as soon as possible.

Frequently Asked Questions about dog gastroenteritis

Can dogs recover from gastroenteritis without treatment?

Yes, in some cases. Acute gastroenteritis in dogs is often self-limiting and will resolve in 24–48 hours, much like humans with an upset stomach. However, seeking veterinary advice is always a good thing to do.

What should I feed a dog with gastroenteritis? 

If at all possible, get a special highly digestible food from your vet. Feed your dog frequent small meals.

Is gastroenteritis contagious between dogs? 

In most cases, no, but some diseases can be contagious, so always be careful and keep your dog’s vaccines up to date.

Reviewed by Becky Mullis, DVM, DACVIM (Nutrition) and Emma Milne BVSc FRCVS.