The Complete Dog Diarrhea Guide

dog diarrhea guide dr franck vet

If you’ve ever had a dog, I’m sure you’ve probably had a diarrhea problem too.

It’s almost a guarantee!

Indeed, this problem of the digestive system is certainly among the most common reasons for consultations. 

So Dr. Franck, why is it so common and what can you do when your dog has diarrhea?

As is often the case in my articles, I can’t only answer you in one sentence. But don’t worry, we’ll come back to that very quickly.

So what is diarrhea anyway?

According to the Larousse dictionary, it is a ‘too frequent emission of liquid or pasty stools, due to a defect of water reabsorption by the intestine’.

In plain English, let me sum it up for you:

your dog has stools more often, they have an abnormally soft consistency and the intestine is not doing its job properly!

Of course, blaming the bowel is easy.

In reality, the bowel is often the victim in these situations because it tries so hard not to let this unfortunate mishap happen.

One of the things that sometimes bother dog owners is that diarrhea can actually be represented by a wide variety of symptoms.


  • it’s a little soft or completely liquid
  • it’s brown or black or gray or red
  • there’s a lot of it or not so much
  • it’s with mucus or not
  • it’s with fresh or clotted blood
  • it looks painful
  • our dog doesn’t even realize it (we’re talking about incontinence here).

In short, the signs are highly variable from one dog to another, and from one day to another.

Then, like many digestive disorders, there are some diarrheas that will resolve themselves and others that will absolutely need to be treated if we don’t want more serious consequences (for which hospitalization is necessary).

Causes of diarrhea in dogs

Dr. Franck, I would like to know more about the possible causes of diarrhea, please. I imagine there must be several?

Yes, you are right!

It would be impossible to go through all the causes of canine diarrhea because there are so many. Fortunately, we can name the most common causes.

This allows the dog owner to have a better idea of what is most likely, and thus to decide what to do next. 


This is the first cause that will be explained and not for nothing!

Dogs often have access to a wide variety of foods in their diet and it is common for one of these to cause problems. Either it will be poorly digested, or the dog will be intolerant to it, or it will even cause an allergic reaction. In short, the food creates a reaction that leads to an imbalance in the intestine. In all these cases, an easily visible sign will be diarrhea. Sometimes, there will also be the famous V+D+A- trilogy (in veterinary terms, this means Vomiting accompanied by Diarrhea and Anorexia).

When we are at this stage, the level of concern will generally increase. 


Sometimes the digestive system reacts to a problem by creating inflammation.

We talk about all those terms that end in ’tis’:

  • esophagitis
  • gastritis
  • enteritis
  • colitis
  • etc.

In short, this is a reaction of the body trying to fight something.

This can be harmful if it is too pronounced and lead to digestive symptoms.  


Infectious causes are pretty broad! We could have put it on par with the food cause.

There are so many viruses, bacteria, parasites, and even fungi that can affect the dog’s digestive system. Some of these infectious pathogens are quite benign at times, while others will create significant digestive signs. It is in these situations that vaccines and deworming medications are useful for prevention.

Of course, you can never prevent everything and dangerous situations can sometimes arise.

Ask someone who has had a dog with parvovirus, and you will understand more. 

Toxic or medication-related

Some medications are known to have the ability to induce diarrhea, for example, the penicillin family.

This does not mean that you should never give them to your dog, but if you give them and you notice a digestive disorder in the hours or days that follow, it is best to contact your veterinarian and often stop the treatment. 

Obviously, there are toxic products that will cause diarrhea quite easily.

In case of doubt about a product, it is better to abstain.   


Unfortunately, this possibility is very present.

The esophagus, stomach, or intestines can be affected by more or less aggressive cancers depending on the type of tumor found.

Fortunately, cancers should not be at the top of your list of possibilities either, unless your dog is old enough.  

Other (foreign body, lymphangiectasia, pancreatic problem, etc)

As we said, there are so many other causes that can lead to loose stools in dogs.

The famous foreign body is one of the possibilities and dogs are particularly talented in this field!

Some dogs have a habit of picking up anything they find in their mouths. Then, all they have to do is swallow and it’s done! By the way, not all foreign bodies will cause diarrhea because some are quite harmless, while others will cause a rapid obstruction and require emergency surgery. 

Wow, Dr. Franck, I didn’t realize there could be so many reasons for canine diarrhea.

So if I’m worried, when is the right time to see my vet? 

dog diarrhea guide when see vet dr franck vet

When to see the vet

If you’ve read my other articles, you’ll see that I mention ‘common sense’ and that’s what I’m going to suggest here.

So, if your dog is generally healthy, up to date on his vaccines and deworming, hasn’t eaten any different foods recently, and seems energetic as usual, you can probably wait 1-2 days to see the evolution. However, if you take his temperature and it is too high, then it is definitely an abnormal signal. Check out the following article if you’ve never taken your dog’s temperature before. 

Related: Temperature in Dogs: What You Need To Know

As for other signs to watch out for, lack of appetite and vomiting often accompany diarrhea.

Then, at this stage, we will also see a lack of energy and other symptoms that will be added.

In short, diarrhea that is not alone is often more worrisome. 

Preventing diarrhea

Let’s talk about prevention. Can you prevent diarrhea? 

Let’s say yes… and no!  Of course, there are the basics of prevention: don’t give your dog several unknown foods at the same time, don’t give him anything to eat that you think is questionable, keep him up to date with his vaccines and deworming, avoid contact with dogs that are already sick, etc…

For the rest, there is a part of chance. Many diarrheas have unknown causes and can be resolved without knowing why. 

Thank you, Dr. Franck, this is very enlightening!

Home treatment for diarrhea

Let’s try to conclude this vast subject with a last question: what treatment can I do at home if my dog starts having diarrhea?

First of all, I would tell you not to give any remedy from your pharmacy, such as half a tablet of Imodium or any other constipating medication. This will not help the situation and is not a proven effective treatment anyway.

The easiest thing to do is often to give a gastrointestinal dog food (sold as dry kibble or cane) and to give probiotics and/or medicinal clay (often sold over the counter in veterinary clinics).

Cooked rice and boiled chicken can also help out if you’re not well taken. 

That’s it, I think that’s it… 

Tell me, I’m curious: has your dog ever had diarrhea? If so, what happened? 

Further Readings


Source 1Cote’s Clinical Veterinary Advisor: Dogs and Cats, 4th edition. 2020. Leah Cohn, DVM, Ph.D., DACVIM (SAIM) and Etienne Cote, DVM, DACVIM(Cardiology and Small Animal Internal Medicine)