Diarrhea in Puppies: Everything You Need to Know

Written By
Reviewed by
Dr. Sarah Wooten, DVM
11 min read

Updated - Feb 23rd, 2022

You just brought home that cute new puppy and surprise – they pooped a puddle! No big deal, you clean it up, but then it happens over and over again. What should you do?

Let’s go over everything you need to know about puppies and diarrhea so you can get your pup back to their best self as quickly as possible.

The world of your puppy

Puppies are much smaller than their full-grown counterparts and are still developing their immune systems. It can take up to five months for that immune system to mature – and this maturation period is the riskiest time for your little four-legger.

Your puppy will be more sensitive to foods, changes in their diet, intestinal parasites, and infectious diseases during this time. Puppies, because of their undeveloped immune systems as well as their small bodies, lack the reserves needed to fight some health issues. Diarrhea can cause a puppy’s health to go downhill quickly. For that reason, anytime your puppy has diarrhea is time for a vet consultation. 

While dog diarrhea may be a common affliction – and most dogs of all ages will get it from time to time – a puppy faces additional risks since they explore everything in their world with their mouths.

Beyond this, some puppies are at higher risk of diarrhea:

  • Puppies under five months old
  • Toy breeds 
  • Unvaccinated puppies
  • Puppy mill puppies
  • Shelter puppies
  • Puppies who socialize with unvaccinated dogs
  • Puppies who frequent dog parks and trails 

Most common reasons for puppy diarrhea

Knowing the reasons your puppy may have developed loose stools will help you correct the issue faster and know if it’s time to see the vet. Here are the most common reasons for puppies to have diarrhea:

  • Abrupt dietary changes
  • Stress
  • Eating inappropriate objects
  • Intestinal parasites
  • Accidentally eating something toxic
  • Bacterial infections
  • Viral infections

Let’s take a closer look at some common causes for puppy diarrhea:

Dietary Changes: When you bring home a new puppy, you might be anxious about choosing the healthiest dog food for them. Talk to your vet about which foods would be beneficial for your particular puppy.

If you decide to change the breeder food they’ve been eating to a new food, wait for at least a week after you have brought them home, and then transition them over slowly. Typical transition times are 7-14 days with careful supervision for any vomiting or diarrhea. Add their new dog food to their bowl in small increments, replacing their old food gradually until the transition is complete. Your vet is an excellent resource during this time if you have any questions or concerns.

When you transition a puppy to new foods too quickly, diarrhea can develop and wreak havoc in their digestive system. Your puppy can also develop diarrhea from eating too much food, so pay attention to the amount of puppy food you’re feeding them whenever you transition to a new food.

Some puppies may show intolerances to some foods or ingredients, further reinforcing the need to transition them to new foods slowly. You can slow down the transition cycle or even go back a step until you narrow down the problem or see a relief in symptoms. Watch out for symptoms in your puppy like loss of appetite, vomiting, or diarrhea anytime you add a new food to your puppy’s daily diet – and yes, that includes treats.

Stress: You and your family, as well as the puppy, are excited about the new family dynamic, but eventually, your puppy will realize this isn’t just a long playdate. Moving to a new home can be stressful for a puppy who’s never been away from their mother or siblings before.

Meeting new people and new household animals can also be stressful for your puppy. Stress affects the immune and digestive systems of puppies who are especially sensitive. Allowing your puppy some downtime to de-stress – and offering them lots of reassurance – will help them deal with any stress they experience. This is also a good time to get your puppy used to going into a kennel for some quiet time.

Beyond this, things like going to the vet, riding in a car, or doing anything your puppy has not experienced before can lead to additional stress. Just watch your pup and help them separate from a stressful situation if necessary – or offer additional reassurance until they relax.

Ingesting foreign objects: Puppies explore the world with their mouths, which is why they’re famous for dietary indiscretions. That tennis ball is a fun toy, but it may be tasty too. And that sock your toddler dropped – or that plant with the big chewy leaves – is a great chew toy, but it can cause a tummy ache or an intestinal blockage in a puppy. 

You should always supervise your puppy. If you can’t be present with them, it’s best to kennel them until you can. Puppies are easy to kennel train, and a kennel provides a quiet, secure, or safe area they can go to themselves when life gets overwhelming.

If you suspect that your puppy ingested a toxic substance or plant, call the ASPCA Poison Control line or the Pet Poison Helpline. They have fees, but it’s worth it to figure out if what your puppy ate was toxic or not, or if you should notify the vet.

Intestinal parasites: Intestinal parasites are very common in puppies. Their most common parasites are roundworms, hookworms, whipworms, tapeworms, giardia, and coccidia. Parasites are transmitted through poop – your puppy can even reinfect themselves from their own poop if you don’t clean it up regularly!

When your puppy stops to smell that foreign pile of poop on a walk, parasites may have infected the animal that left it and your puppy could inhale an egg or two, giving them worms as well. And when a mother dog has worms, their placenta and/or milk will transfer them to their puppy.

The signs of worms are:

  • Distended belly
  • Slow growth
  • Poor-quality coat
  • Thin appearance
  • Bloody diarrhea
  • Lethargy
  • Worms visible in the poop, puppy may even vomit worms

Your vet will get a stool sample from your puppy on its first visit to check for parasites by putting the sample under a microscope to look for worms, eggs, or protozoa.

Giardia and coccidia are protozoa and are found by using a microscope. One symptom of these parasites is watery, very smelly diarrhea. Puppies often vomit with coccidia as well.

It’s very important to put your puppy on a regular and consistent deworming schedule, along with an at-home prevention program. 

Bacterial infections: Clostridium, listeria, salmonella, and E. coli are the most common bacterial infections puppies get that lead to diarrhea. They contract it by eating rotten food or poop from infected animals. These bacterial infections cause severe diarrhea and dehydration that can lead to organ damage in a few days. 

Symptoms of bacterial infections in your puppy’s gastrointestinal tract are:

  • Vomiting
  • Very foul-smelling, watery diarrhea that may be black or bloody
  • Severe dehydration
  • Pale gums
  • Abdominal pain

These symptoms are a deadly combination, even in adult dogs. If you see them, talk to your veterinarian immediately. Puppies don’t have enough reserves to fight these infections and can go downhill quickly, spelling disaster and heartache.

Viral Infections: “Parvovirus” is a word every puppy parent dreads. It’s a viral infection that’s very contagious and depletes the immune system and body quickly. Parvo (as it’s abbreviated) is often fatal and needs immediate veterinary care.

Symptoms of parvo are:

  • Severe or bloody diarrhea
  • Vomiting
  • Weight loss
  • Lack of appetite
  • Lethargy
  • Fever 

Supportive veterinarian care for parvo includes fluid therapy to replace lost electrolytes and rehydrate the puppy, anti-nausea medication, and antibiotics. Some puppies also require blood transfusions. The vet will supervise your puppy until the symptoms subside, which can take anywhere from 3 days to a week. During this time, your puppy is very contagious to other dogs and should be hospitalized for treatment and prevention of disease spread.

Other viral infections are distemper, canine coronavirus (which is NOT Covid-19), and canine adenovirus. These are all preventable if you time your puppy’s vaccinations well – one missed vaccination can leave your puppy vulnerable to parvo. Your puppy isn’t considered protected until they receive their full puppy series – this is because immunity from the mother’s colostrum protects the puppy for a while but interferes with vaccination efficacy. For that reason, make sure your puppy only interacts with dogs that are vaccinated until they receive their full series of 3 to 4 boosters.

Puppy diarrhea and home care

Not all cases of diarrhea require vet care, but you should always check with your veterinarian if your puppy has loose stools. We can cure some diarrhea with home remedies or home care. But how do you know? What should you do?

Let’s dive in!


The old saying that an ounce of prevention is worth a pound of cure is true for puppies and their health. Diarrhea is common in curious young pups, but some diarrhea is preventable. Here’s how.

Vaccinations: Regular checkups with the vet and timely puppy boosters will reduce the likelihood of viral diarrhea for which vaccination is available. As parvovirus is a fatal disease that is expensive to treat, it makes sense to prevent it with an inexpensive vaccine that has been effective at reducing the disease for over 30 years.

Gradual dietary changes: Dogs of all ages can suffer from gastrointestinal upset when transitioning to a new food. Puppies are no exception – in fact, they’re more sensitive to dietary changes. Whenever you change their regular diet, transition gradually to avoid digestive issues, food intolerances, or food allergies. Your vet can help you work out a transition schedule that meets your puppy’s health needs.

No table scraps: A complete, balanced puppy food is all your puppy needs, except for maybe some healthy training treats. Table scraps can contain many ingredients, additives, and seasonings that can be dangerous for your pup. Avoid feeding them to your puppy – and teach your puppy that the table is for humans and not a puppy snack smorgasbord.

Deworming schedule: Parasites can slow your puppy’s growth and cause all kinds of health problems, including infecting you and your family. A regular deworming schedule – along with picking up all poop from the yard – can help your puppy remain parasite-free. If you suspect worms, take a stool sample to your vet for analysis.

Pick up poop regularly: Puppies can reinfect themselves by eating their own poop. Picking it up from the yard makes that less likely.

Get dog-friendly plants in your house and yard: Your mouthy puppy will taste anything, so you want to avoid having toxic plants around for them to use as a chew toy or snack. If you do have toxic plants in the house, fencing them off (or removing them) will keep your sneaky explorer from getting sick by eating things they shouldn’t.

Crate unsupervised puppies: When you can’t supervise your puppy, put them into their crate for safety. They won’t have access to foreign objects or garbage and can’t chew your furniture or relieve themselves on your carpet. 

Dogs prefer dens, and a crate will become their quiet, safe place. As long as kennel time isn’t a punishment or they spend inordinate amounts of time in one, a crate or dog kennel can keep your puppy safe and give them a de-stressing area when they need it.

Avoid dog parks,  popular dog trails, and adult dogs with unknown vaccine history until your puppy has all their puppy boosters: Until your puppy’s vaccinations are complete, don’t allow them to come into contact with possibly infected feces or animals, or places where you might encounter them. This includes unvaccinated dogs, dog parks, elimination areas in your apartment complex, and popular dog-walking trails. 

What to do when diarrhea happens

If your puppy develops diarrhea, always talk to your vet first. Especially if it involves diarrhea and vomiting, the deadly combination for young puppies.

If your vet feels you can manage the diarrhea at home, here are some tips:

Fluids, fluids, fluids. Try giving your puppy water, sodium-free broth and pediatric fluids to replace the lost fluids and electrolytes.

Give their system a rest. Give your puppy’s digestive tract a break. Try feeding your puppy small amounts of broth every hour or so for one day to rest the GI tract. Always consult with a veterinarian before fasting a puppy, however, as this can cause hypoglycemia in very small puppies. 

Bland diet. A slurry of sodium-free broth, boiled chicken, and plain white rice is easy to digest once your puppy is ready to eat again. You can offer small amounts of this mixture for several days to get your puppy through their bout of runny poop. If diarrhea lasts longer than several days on a bland diet, consult with your veterinarian. 

Other home remedies. Talk to your veterinarian about offering organic canned pumpkin, probiotics (which are always helpful for young puppies), or kaolin-pectin to your puppy. These can help solidify their poops.

If diarrhea continues, another chat with the veterinarian and some lab work may be necessary, but many common diarrhea problems resolve themselves with minimal veterinary care.

The last word on puppy diarrhea

Diarrhea is common in puppies because they explore their worlds with their mouths. Using simple prevention tactics, deworming schedules, and timely puppy vaccinations can eliminate or reduce most causes of diarrhea, leaving your puppy to thrive, grow properly, and become the stunning adult canine you know they’re destined to be.

When your puppy falls unexpectedly ill, you want to get them the best care pawsible. Pumpkin’s puppy insurance plans can help pay for 90% of covered vet bills to help you do just that.

*Pumpkin Pet Insurance policies do not cover pre-existing conditions. Waiting periods, annual deductible, co-insurance, benefit limits and exclusions may apply. For full terms, visit pumpkin.care/insurancepolicy. Products, discounts, and rates may vary and are subject to change. Pumpkin Insurance Services Inc. (Pumpkin) (NPN#19084749) is a licensed insurance agency, not an insurer. Insurance is underwritten by United States Fire Insurance Company (NAIC #21113. Morristown, NJ), a Crum & Forster Company and produced by Pumpkin. Pumpkin receives compensation based on the premiums for the insurance policies it sells. For more details visit pumpkin.care/underwriting-information and pumpkin.care/insurance-licenses

Lynn Guthrie

Writer, Mom of a Fab Fur Fam of Five
Lynn is a writer and long-time Learning & Development Manager at a large PNW retailer. She's also mom to 3 dogs & 2 cats!
Reviewed by Dr. Sarah Wooten, DVM
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