About Puppy Diarrhea

Puppy diarrhea is SO common that your new pup is likely going to have at least one episode of loose stools during his first few weeks with you.

Yorkshire Terrier with puppy diarrhea

The causes of diarrhea in puppies can include:

  • changes in diet 
  • stress 
  • parasites
  • illness/disease
  • eating stuff he shouldn't

Although your little guy might get 'the squirts' from something as simple as a sudden change in puppy food or getting into the trash can, loose stools can also be the first sign of several serious illnesses including Canine Parvovirus, Coccidiosis and Giardia.

To jump straight to puppy diarrhea treatment options CLICK HERE

If your puppy has loose stools it's a sign that something is not right with little Fido's digestive system. 

Diarrhea should never be ignored and if it happens repeatedly, there is blood or mucus, or your puppy is vomiting too then it's important to get a professional veterinary evaluation asap.

Learn more about the causes of:

Mild - Moderate Puppy Diarrhea

Diarrhea in puppies can range from a soft 'pile' to a jet of water... and just about everything in between!

If your pup has a couple of soft, chocolate-pudding-type stools, don't panic right away. 

This type of diarrhea in puppies usually doesn't last for more than 24 hours and can be caused by a simple tummy upset.

About puppy diarrhea

Your little guy might act totally normal, or he might seem a little quiet or look sorry for himself, but he shouldn't look really ill, be inactive, or refuse a drink or a treat (even if he doesn't want his dinner).

Mild to moderate diarrhea in puppies can be caused by:

A Change In Diet

When you pick up your new puppy home, it's a good idea to ask what type of puppy food he's been eating up to this point and then make sure you stick with that for the first week or so because suddenly switching your puppy from one brand of food (or from dried to canned, commercial to home-made etc) is one of the most common causes of puppy diarrhea.

If you decide you want to change the brand of food your new pup is eating that's fine, but make the transition slowly.


A puppy's digestive system can be fairly delicate and is easily affected by stressful situations. Things such as leaving their mom and siblings, a visit to the veterinarian, getting used to a new home environment, excess excitement or exercise and so on, can trigger a bout of loose stools.

Stress can also allow a parasitic infection called Coccidiosis to take hold. These parasites exist in most pups/dogs, but are kept in check by the immune system.

When a young puppy is stressed, his immune function is repressed and coccidia can flourish. If your puppy's diarrhea gets worse quickly, is watery or is tinged with blood/mucus then coccidia or a viral/bacterial disease might be the problem.

Eating Something He Shouldn't

Little puppies are endlessly curious, and often seem to believe that EVERYTHING is edible, until proven otherwise! 

If your pup has been snacking on left-overs from the garbage can, the flowers or dirt in your front yard, the cat's food, newspaper, crayons, or some other 'inedible' stuff, then he's most likely going to have at the very least some loose stools, possibly some diarrhea and/or even vomiting.

A surprising number of every-day foods and other items are toxic, or dangerous for your puppy to ingest. You can find a list of the ones most likely to cause trouble on my Poisonous Foods page.

If your pup has a mildly upset tummy and this type of diarrhea, a good probiotic can help 'reset' his system. I'd recommend Nutramax Proviable.

It not only rebalances his digestive system by encouraging the growth of good bacteria, but also helps to firm up stools. Nutramax Proviable probiotics are available in two formulas:


Dog food allergies and sensitivities are more common than many owners realize, and these can cause diarrhea in puppies, and dogs. True allergies are more likely to cause skin irritation or inflammation and itching, whereas a 'sensitivity' to an ingredient may cause loose stools or even vomiting.

High-protein puppy foods are also more likely to cause loose, unformed stools in some puppies.

Other Canine Health Conditions

There are a number of canine diseases or conditions which can cause chronic diarrhea in puppies and/or dogs.

These include:

  • Pancreas problems
  • Inflammatory bowel conditions (including Colitis)
  • Liver disease
  • Gall bladder problems
  • Adrenal issues
  • Tumors

......and more.

Some breeds seem to be predisposed to conditions which cause chronic loose stools.

These include:

  • Shetland Sheepdog
  • Collies
  • German Shepherd
  • Irish Setter
  • Boxer
  • King Charles Spaniel
  • Golden Retriever
  • Miniature long-haired Dachshund
  • French Bulldog
  • Yorkshire Terrier
  • Soft-coated Wheaten Terrier

Moderate - Severe Puppy Diarrhea

If the diarrhea is liquid (anything from soupy to watery) then it is time to worry. I'm not saying that you need to panic, but you definitely need to get your little one to your veterinarian as soon as you can.

If your puppy has repeated, watery diarrhea that contains blood and/or mucus, or looks black,  it's likely to be an emergency situation and you need to get him to a vet right away!

Watery and/or bloody diarrhea in puppies and dogs is usually caused by one of three things.....

Parasitic Infection

Your puppy could have developed an infection caused by parasites, such as Coccidiosis or Giardia, both of which can cause pretty severe, foul smelling diarrhea (sometimes accompanied by vomiting, lethargy and loss of appetite).

A bad case of puppy worms (particularly roundworms, whipworms or hookworms) can also result in your pup suffering from diarrhea and/or vomiting.

You might also notice that his stools contain a lot of mucus because the worms cause a lot of internal irritation. This is most often seen in very young puppies who haven't been dewormed yet, or older pups who have never been treated for worms, or not treated often enough.


Many of the most contagious, serious (and often potentially deadly) dog illnesses have diarrhea as one of the earliest symptoms.

This kind of diarrhea is usually very watery, and can contain mucous and/or blood (shows as red or brown). It's usually frequent, and may spray or 'jet' out with some force.

Dog diseases such as DistemperCanine Parvovirus, Hepatitis and Corona Virus are just some of the possible reasons for this type of puppy diarrhea and all of them need emergency treatment.

As I mentioned above (and can't stress enough!), watery diarrhea that's has streaks of blood or contains mucus is a red flag. Don't 'wait-and-see', get veterinary help IMMEDIATELY. Your puppy's life could literally depend on it.

Internal Bleeding

Black or 'tarry' looking stools could be a sign of internal bleeding. The blood could be coming from Fido's stomach or his small intestine.

Trauma to the belly is the most common cause of internal injuries and bleeding, but diseases such as Parvovirus, Diabetes or cancer can also cause blood loss like this.

Dehydration is serious, potentially fatal

Whenever a pup has loose stools and/or vomiting dehydration is a concern.

Make sure your pup gets plenty of fresh water to drink.

If he can't/won't drink or is unable to keep water down or has continued watery diarrhea he may need IV fluids and definitely needs to be checked out by a vet asap.

Puppy Diarrhea Treatment Options

There are many options for treating puppy diarrhea and which one you choose depends on what type of diarrhea your pup is experiencing and what's causing it.

For mild diarrhea in puppies fasting, probiotics, natural supplements and certain OTC products or supplements can be helpful.

For moderate to severe diarrhea veterinary care is essential and your vet has access to a whole range of medications and protocols to help your pu make a full recovery.

Don't wait-and-see, act now.... Click here to learn how to treat puppy diarrhea.

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