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The Causes of Diarrhea in Puppies

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Layne has worked in veterinary medicine for almost 10 years and is a licensed veterinary technician.

Reasons Why Your Puppy Has Diarrhea

Reasons Why Your Puppy Has Diarrhea

Why Does My Puppy Have Diarrhea?

If you recently welcomed a puppy into your home, congratulations! Puppies are so cute, but they are also a lot of work (you might now just be realizing this!) and they come with their challenges as well. Puppy diarrhea is not all that uncommon, but it’s important to figure out what is causing the diarrhea first, and quickly.

While a number of changes can be behind the diarrhea—including parvovirus, changes in food, parasites, and stress—stopping it is important. Puppies are small and dehydrate quickly and can “fade” easily. In the worst of cases, severe diarrhea, when caused by viruses or infection, can result in death. From mild to moderate to bloody or severe diarrhea, find out what is causing your puppy's gross poop. When in doubt, take your puppy to the vet ASAP.

Causes of Diarrhea in Puppies

  1. Changes in Diet (changes in food or treats)
  2. Viruses
  3. Parasites
  4. Bacterial Infections
  5. Stress
  6. Ingestion of Foreign Objects (toxins and trash)

What causes bloody diarrhea in dogs?

Bloody diarrhea is often caused by viruses, gastrointestinal damage (from parvovirus or secondary bacterial infection), parasite infestations (giardiasis), stress (stress colitis, though rarer), and ingestion of foreign objects from impactions.

1. Changes in Diet or Food

If you are weaning your puppy off formula or you adopted your dog from the shelter, changing their food up immediately can give them diarrhea. Dog foods, though seemingly uniform, come with many added ingredients and variances—from grain-free to hypoallergenic—so changing your puppy’s food or treats can give them the runs.

How to Fix Their Upset Stomach

Take some of the food your puppy has been on and transition them gradually. First, mix only a little new kibble or wet food in with their standard food. Over a week, change the ratios to 4:1, 2:2 (split half and half), and 1:4 (old to new). Eventually, you will get them onto the new food with fewer problems. Ween them gradually.

Keep Treats to a Minimum

Keep treats to a minimum and go for organic and wholesome products. Freeze-dried treats have minimal added ingredients and are fairly hypoallergenic. Some vets might recommend giving your puppy vet-approved probiotics (often powdered) or a diet of boiled, boneless, skinless chicken breast and unseasoned white rice to help firm up their stool. For constipation, you can offer unseasoned pumpkin per your vet’s direction.

2. Viruses

Canine parvovirus is a very common cause of diarrhea. Black and tan dog breeds are particularly prone to acquiring parvovirus (Rottweilers and German Shepherds), but any breed or mix can be susceptible.

Vaccinate Your Dog!

It’s important that your puppy receives its regular vaccines series prior to being exposed to other puppies or dogs or simply walking in your backyard. Vaccines can start as early as 6 weeks and will be given in a series of three. Most shelters will start the DHPP vaccine at 6 to 8 weeks. This is considered a core vaccine and covers distemper, adenovirus (hepatitis), parainfluenza, and parvovirus. Canine parvovirus or “parvo” is extremely common in the environment and extremely hardy. It can be spread via old stool, dog-to-dog contact, and can be picked up in various environments.

How Can I Tell If My Dog Has Parvo?

Puppies with parvovirus often become extremely lethargic and quiet and then will present with a fever, diarrhea, vomiting, and loss of appetite. Without supplemental therapy and support, they can die within 48 to 72 hours. (Several other less common viruses can result in diarrhea.)

Puppies will eat whatever they can find.

Puppies will eat whatever they can find.

3. Parasites like Giardia and Coccidia

Giardia and coccidia parasites are fairly common in shelter dogs and puppy mill dogs (dogs that are bred in unhealthy conditions—often purebreds). Once diarrhea sets in with giardiasis (giardia is a microscopic parasite found in soil, food, and water) the puppy will show signs of illness. It is possible to transfer giardia to humans and vice versa, so it’s extremely important that you get your puppy treated and wash your hands, especially if you have kids. Giardia can and will cause watery, liquid stool and blood.

What Does Giardia Look Like?

  • Watery stool
  • Runny stool
  • Bloody stool
  • Foul-smelling
  • Yellow-brown-gray in color

Is Giardia Common in Puppies?

Yes, it is fairly common in puppies, so don’t necessarily panic. The issue with giardia is that the parasite will destroy your puppy’s intensities even with treatment and can cause malnutrition, so it is important that you get a prescription from your vet and treat your puppy right away. Your vet might ask you to take in a stool sample and they will often run a test in the clinic to diagnose this quite immediately (fecal flotation under microscope, ELISA snap test or fecal PCR).

How Did They Get It?

Your puppy likely got giardia from a contaminated surface like stagnant water or grass. Sometimes the infection goes away on its own but it often becomes chronic and almost always requires veterinary care. Metronidaole (Flagyl) is often prescribed and is a very common antibiotic for treating giardiasis.

How Long Does It Take for It to Go Away?

With treatment and care (antibiotics or antiparasitics), probiotic support, and hydration, giardiasis usually disappears in less than two weeks.

What Is Coccidia?

Coccidia is another common shelter dog (or outdoor dog) parasite and often produces foul-smelling, watery feces, vomiting, and frothy-white, filmy diarrhea (it smells bad!). Coccidia is often treatable as well, but it’s important to practice good hygiene when helping your puppy recover.

4. Bacterial Infections

Bacterial infections can also cause diarrhea in puppies and you might also notice fever, vomiting, lethargy, anorexia, and bloody stool. Common parasites like Salmonella, E. coli, and clostridium can cause bacterial-related diarrhea in dogs.

There might also be a culprit behind the bacterial infection such as parasite infestations (worms) and/or viruses that can lead to secondary bacterial infections and digestive issues. Similar to humans, bacterial infections can be treated with proper veterinary care.

5. Stress and Anxiety

Yes, stress and anxiety can cause diarrhea in puppies! It is hard for a little puppy to adjust to a new environment or big change, even to be separated from mom or the litter. Being in a new house with new sights and smells can really stress a puppy out.

Just like in humans, stress wreaks havoc on the body and can cause a dog (or human) to have loose stool and indigestion. Dogs, too, are prone to intestinal upset with stress, anxiety, and change. It’s important to give your dog a good head start in life and offer them a secure and loving home. If the diarrhea continues, make sure you visit your vet. Some remedies like Adaptil (a calming aid) can really help a new pup to feel relaxed. Consider several options here.

Help your puppy to feel comfortable in their new home.

Help your puppy to feel comfortable in their new home.

6. Ingestion of Foreign Objects or Toxins

Puppies will eat anything and everything they can find, but unfortunately, this means they might consume something without your knowledge but the only sign to show for it is diarrhea.

Contrary to popular belief, a blocked intestine (such as a chewed-up toy blocking the intestines) or something uncomfortable in the stomach (like wood, plastic, or trash) can cause bloody diarrhea and vomiting or worse. This is called an impaction and foreign body ingestion.

Often, these types of issues require surgical removal (which is expensive!). Your puppy can die if you do not get them adequate veterinary care. The same can be said for toxin ingestion. Puppies will eat anything around the house including fertilizer, cleaning products, coffee grounds, antifreeze–you name it, and diarrhea can often be a symptom of toxicity. Get them treatment fast!

Adaptil for Anxiety

Don't Skip the Vet!

If your puppy has chronic diarrhea, please take them to the vet. Puppies can fade quickly and even pass away from severe dehydration and malnourishment without adequate support.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2020 Laynie H


Laynie H (author) from Bend, Oregon on August 15, 2020:

Hi Liz, puppies are a ton of work, agreed!!! Not only is training so much work but they often have many accidents in the house and diarrhea becomes quite overwhelming very fast!

Liz Westwood from UK on August 15, 2020:

They might look very cute, but your article helps to warn new owners about some of the health issues their new puppy might have. It's bad enough trying to get a young puppy trained without having to clear up more mess due to a upset stomach.