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Diarrhea in Dogs – the Most common causes and fixes for good gut health

Good dog pooping

In a perfect world, dogs would never get sick. And their stools would be perfectly formed.

But even if you kept them at home all of the time, there is a very good chance that at some stage they would get Diarrhea or at least loose stools. You might also be surprised that its one of the MOST common dog ailments seen by vets.

In the short term its not a lot to panic for, and it can right itself, but prolonged diarrhea is very bad because it stops nutrition to the dog, causes them pain, and can usually indicate a bad underlying condition.

This article is based on a recent case of our spoodle Archie in September 2022. He has been on a half raw, half kibble diet for the more mature years, and that has generally gone well. The kibble was mostly to ensure he got enough fibre, as he purposely avoids vegetable matter (unless it’s laced with meat-based attractants in the form of kibble). His lineage also comes from half poodle stock that are known for allergies, and skin and stomach sensitives.

Puppies, pregnant dogs and mature dogs an also be more susceptible to things like bacterial infections and take longer to right the balance of good bacteria in their gut, so knowing what is going on and you first DIY actions at home as soon as you sense an issue is vital to keeping your dog well.  Secondary infections because of lowered immunity is the last thing you and them need.

 Dog Diarrhea definition

Diarrhea (all species) is caused by faster movement of faecal material through the intestine.

The high speed can be caused by many diseases (short term or chronic) but all mean :

  • decreased absorption of water into the body (causing dehydration and drinking of a lot of water),
  • Decreased nutrient uptake – including proteins that are required for many main functions of the body from brain, to heart, to general organ maintenance,
  • Decreased electrolyte absorption – affecting MANY body systems.

Any one of these malabsorption issues is an issue, but all three basically means your dog is starving. This is all complicated by the fact that they have a carnivore’s digestive system that includes a very short intestinal tract (built to get rid of toxic waste load, very quickly).

Gastrointestinal transit time for most dogs is six to eight hours but 20-30 for people. While  dogs food transit time is typically 6-8 hours maximum. You can understand if your dog has diarrhea and food is shooting through much faster, the nutrient absorption time (assuming that the intestine is still functioning to absorb any food) is Much less.

Any diarrhea is serious in dogs, but some are short term and easy to solve (once you have found the cause, others are more serious but treatable others indicate a chronic or terminal disease … “Diarrhea can also be a sign of a more serious underlying disorder such as allergies, bacterial or viral infections (such as parvovirus), inflammatory bowel disease, organ dysfunction, or other systemic illnesses.  “ ref 1

Its worth noting these in more detail:

Common causes when the only symptom is dog diarrhea with relatively simple fixes.

caused by intestinal infection from:

  • A: bacteria
  • B:  viruses such as coccidia, or intestinal worms (hookworms, roundworms, whipworms) may be the cause.

A    BACTERIA – like all animal’s dogs gut biome has “good” and “bad” bacteria. 

The good bacteria is there to synergistically work with the intestine in breaking down food and separating the waste to expel. When a dog gets sick from a viral infection or otherwise, lowered immunity can have the bad bacteria population grow unchecked and swamp the intestines good bacteria’s ability to break down the food and nutrition they need. And that food just goes sailing on by.

B  viruses such as coccidia or dog covid. 

Coccidia is a single-celled parasites that live in the wall of your dog’s intestine and they can get from eating soil that contains dog poo. I have seen almost every member of our dog pack eating soil at some stage and just hope that it doesn’t include anything more serious like the parvo virus. Even with immunisations against parvo, some dogs can still get it.

And it does cause chronic diarrhea – hence why we are ruling out the less serious and easily treatable causes first.

C   intestinal worms (hookworms, roundworms, whipworms)

These worms will always exist in nature, but it’s the very reason why we always ensure our dog gets his monthly intestinal worm, flea and heart worm tablet. The tablets might not be 100% affective, but they seem to be pretty close to that for the majority of dogs – and the simplest method you can use to protect your dog from this cause of diarrhea ALL year round.

2   THINGS that happen at home

A  = Stress or anxiety – caused by a change of home, change of family membership (people leave), or any other stressor the dog picks up on.  If you have had a major change in your life recently, and your dog starts acting strange and having Diarrhea – it might be connected.

B  = Change in diet or treats  –  This is often a ‘red herring’ that large dog food companies want to put out there to prevent you from swapping to another brand.  Yes if a dog eats a new food with an ingredient they are legitimately allergic to, they can get Diarrhea and many other side effects.

But we have happily changed up our dogs meals most night (at least in the meat component) – from raw beef, to cooked chicken breast, to canned fish (tuna, salmon or sardine in Springwater).

To recap – dog diarrhea can result from any of the following:

  • Eating garbage or spoiled food
  • Ingestion of foreign objects such as toys, bones, and fabric
  • Ingesting toxins or poisons (plants or commercial)
  • Medications such as antibiotics
  • Parasites – roundworms, hookworms, whipworms, Coccidia, or Giardia
  • Viral infections such as parvovirus, distemper, or coronavirus
  • Bacterial infections – such as salmonella
  • Inflammatory bowel disease (vet drugs can resolve)
  • Pancreatitis (low fat diet can assist)
  • Colitis
  • Liver or kidney disease
  • Intestinal cancer


Short term Diarrhea may not seem like much of an issue, but dogs often suffer in silence. This is why you need to check your dog’s stools every time you take them for their daily walk.

For years I thought loose stools were just what a dog allergy prone was going to have. We tried to change up so many different forms of kibble, and started cooking all raw red meat products, but nothing much seemed to change.

We thought higher fibre levels in kibble might be the solution but they just made the food blander and gave our dog less enjoyment in eating, and with not any real change.

We soon found that our dog wasn’t allergic to any of the proteins in the meats, but didn’t do well on high level of fats from pork or lamb.  Lean meats of any kind were fine, just cooked roast offcuts did the damage.

We also read up on fibre and realised that there are many different forms of fibre.  The semi fermentable are the types that should be in your kibble to provide just the right amount of food for the bacteria in their intestine to feast on and create the right by product chemicals for dog health.

Then we made sure that they had sufficient NON fermentable fibre, that would essentially easily pass through them, non-digested, but would clean out their intestine, and bind the waste products together for solid stools.

The final part of the puzzle was adding sufficient probiotics as they aged.

Mature dogs often lose the ability to make enzymes that break-down food properly or find it hard to colonise good bacteria in their intestine. The probiotics that are often in dog probiotic powders, OR human grade probiotics are NOT the same as found in the dog’s colon – but seem to make a difference by making the intestine more hospitable for colonisation of the good bacteria that are already there.

We have also had success at feeding activated charcoal via our charcoal biscuits.  These soak up excess acid and bile that dogs can produce when they are sick, and provide a more solid substance to slow down speeding waste in the intestine.

When our dog drinks from smelly puddles of water that have been stagnant for a while, and dogs have urinated in, he has loose stools again. We try and put him on lead in areas where we think he will find these puddles, but if we miss out, a few days of probiotics often helps solidify the stools again.

For many people ensuring their dog’s stools can be an endless mission, but following these few simple guidelines and working out specifically what works with their dogs biome is the end goal to get the optimum results, and optimum nutrition uptake.

Consult a vet if you have any questions about any major changes to your dog’s diet or continued loose stools.  Loose stools can be a major side affect of a major illness or infestation and should be treated with care.



Ref 1  Diarrhea in Dogs   – By Ryan Llera, BSc, DVM; Krista Williams, BSc, DVM; Ernest Ward, DVM

vcahospitals .com/know-your-pet/diarrhea-in-dogs


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