Why Does My Dog Keep Getting Diarrhoea?

If your dog keeps getting diarrhoea that settles and then comes back, that pattern isn't normal - even if they seem well in between. Recurrent diarrhoea in dogs usually points to something ongoing: diet, parasites, stress, digestive or pancreatic problems, past antibiotic use, or a disrupted gut microbiome. A good rule of thumb is that at least 90% of a dog's poos should look normal. If you're nowhere near that, it's worth investigating why.

"My dog keeps getting diarrhoea, but then it gets better again" is something we hear surprisingly often in consults. A dog might have perfectly normal poos for a week or two, then a few days of soft stools, mucus or diarrhoea before everything seems to settle again. An occasional imperfect poo happens. Recurrent diarrhoea isn't something we'd consider normal.

A simple rule of thumb: at least 90% of a dog's poos should look normal. They should be formed, easy to pick up and reasonably consistent from day to day. If you're regularly seeing soft stools, mucus, urgency or episodes of diarrhoea - even if things look normal in between - it's worth asking why.

Why does my dog keep getting diarrhoea?

There are lots of reasons a dog can have recurrent diarrhoea. Common causes include:

• Diet - a sudden food change, rich treats, scavenging, or an ingredient that doesn't agree with an individual dog
• Parasites and gastrointestinal infections
• Previous antibiotic use
• Stress, via the gut-brain axis
• Pancreatic or digestive problems
• Chronic gastrointestinal disease
• Disruption to the gut microbiome

Sometimes there is more than one factor involved, which is why repeatedly treating individual episodes of diarrhoea doesn't necessarily solve the bigger problem.

It's the gut environment, not just the episode

When working through recurrent gut problems, one of the most important things to look at is the environment inside the gut. The gastrointestinal tract contains an enormous community of bacteria and other microorganisms, collectively known as the gut microbiome.

It's tempting to divide these into "good bacteria" and "bad bacteria", but gut health is much more complicated than that.

Many bacteria that get blamed for diarrhoea can also be found in healthy dogs. What matters is what is allowing particular organisms to thrive, what the rest of the microbial community looks like, and how that community is functioning. Diet, fibre, digestion, inflammation, antibiotics and other medications can all influence this environment. Even stress can affect the gastrointestinal tract through the gut-brain axis.

So rather than only asking how to get rid of a particular bacterium, it's worth asking why the gut environment is allowing it to flourish in the first place. That's often a much more useful way to think about recurrent gut problems.

Curious what's happening inside your dog's gut? A dog gut microbiome test is a simple at-home stool sample that maps your dog's microbial community, so you and your vet can look at patterns rather than guessing between episodes. Explore the dog gut microbiome test

What about Clostridium and E. coli in dogs?

This comes up frequently when interpreting gut microbiome results. Finding bacteria such as Clostridium species or E. coli doesn't automatically mean they are responsible for a dog's diarrhoea. These organisms can be present in the gastrointestinal tract without causing disease - so finding an organism and finding the cause of the problem aren't necessarily the same thing.

Things worth considering:

• how abundant particular organisms are
• what else is happening within the microbial community
• the dog's diet and clinical history
• whether there are other relevant findings

Think of the microbiome as an ecosystem rather than a list of individual bacteria. Focusing too heavily on one organism can mean missing what is happening in the wider gut environment.

When should recurrent diarrhoea in dogs be investigated?

This is where the 90% rule can be useful. If a dog's poos are normal at least 90% of the time, they're otherwise completely well, and there's an obvious explanation for an occasional soft stool, that's generally less of a concern.

If you're nowhere near 90% - particularly if there is regular mucus, urgency or diarrhoea - it's worth investigating further.

That doesn't automatically mean microbiome testing. Depending on the individual dog, this might involve:

• faecal testing
• blood tests
• a dietary assessment
• pancreatic or nutrient testing
• imaging
• further gastrointestinal investigation

A dog gut microbiome test can be another piece of that puzzle, allowing a closer look at the microbial community and helping identify patterns that may explain what's happening within the gut.

The important part is interpreting those results alongside the dog in front of you. A microbiome report should never exist in isolation from the dog's symptoms, diet and clinical history.

The 90% poo rule

Perfect poos every single day isn't the expectation, but a dog having diarrhoea every few weeks shouldn't be normalised simply because "that's what they've always been like."

Aim for at least 90% normal poos.

If you're not getting close to that - particularly if your dog keeps getting diarrhoea - it's worth looking beyond each individual episode and considering what might be happening within the gut environment. That's often where a much better understanding of the problem starts.

Ready to look beyond the next episode?

If your dog's poos aren't hitting the 90% mark, an at-home gut microbiome test is a straightforward first step. Collect a small stool sample at home, post it back, and get a report to work through with your vet.

Order your dog's gut microbiome test

Not sure if it's the right next step? Read more about how the test works or talk to your vet about your dog's individual history.

Dr Nicole Rous, Integrative Veterinarian and Co-founder, i-screenPets

When to see your vet urgently: if your dog has severe or persistent diarrhoea, blood in their stool, vomiting, weight loss, lethargy or is otherwise unwell, please seek veterinary advice. This article is general information and is not a substitute for individual veterinary care.

FAQs

Why does my dog keep getting diarrhoea and then getting better?

A pattern of normal poos followed by a few days of soft stools or diarrhoea usually means something ongoing is driving it - diet, parasites, stress, digestive or pancreatic issues, or a disrupted gut microbiome. Treating each episode alone may settle the symptoms without addressing the underlying cause, which is why the problem keeps returning.

How often is too often for a dog to have diarrhoea?

As a rule of thumb, at least 90% of your dog's poos should look normal - formed, easy to pick up and consistent day to day. An occasional imperfect poo happens. Regular episodes of diarrhoea, mucus or urgency are worth investigating, even if your dog seems well in between.

Is mucus in my dog's poo a problem?

A small amount of mucus occasionally can happen, but regular mucus is one of the signs that suggests the gut isn't settled. Combined with soft stools or urgency, it's a reason to look further rather than wait for the next episode.

Can food cause recurring diarrhoea in dogs?

Yes. Sudden food changes, rich treats, scavenging or a specific ingredient that doesn't suit an individual dog can all affect stool quality. Diet also shapes the gut environment over time, so it's one of the first things assessed when working through recurrent diarrhoea.

Does finding Clostridium or E. coli mean that's what's causing the diarrhoea?

Not necessarily. Both can be found in healthy dogs without causing disease. What matters is how abundant they are, what the rest of the microbial community looks like, and how that fits with the dog's diet, symptoms and clinical history. Finding an organism and finding the cause aren't the same thing.

Will probiotics fix my dog's recurring diarrhoea?

Probiotics can be useful for some dogs, but they're one input into a much bigger system. If something is continuing to disrupt the gut environment - diet, stress, parasites or an undiagnosed digestive problem - that usually needs addressing too. Talk to your vet before starting anything new.

What does a dog gut microbiome test show?

It maps the community of bacteria and other microorganisms in your dog's gut, showing which organisms are present, how abundant they are and how the community looks overall. It's one piece of the puzzle and should always be interpreted alongside your dog's symptoms, diet and clinical history.

When should I take my dog to the vet for diarrhoea?

Seek veterinary advice promptly for severe or persistent diarrhoea, blood in the stool, vomiting, weight loss, lethargy, or if your dog is otherwise unwell. Also see your vet if diarrhoea keeps recurring, even when your dog seems fine in between.