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7 Common Reasons for Nighttime Diarrhea in Puppies

Raising puppies is challenging.  There are so many things to remember including vaccinations to removing unwanted objects from your puppy’s mouth.

As if that wasn’t enough to worry about, diarrhea in puppies can rear its ugly head.

Diagnosing Diarrhea in Puppies is Scary and Frustrating

Diarrhea in puppies is a frustrating symptom for dog owners.  It might signal anything from a potentially fatal infection to ordinary indigestion.

Anyone who has searched “puppy diarrhea” knows that many significant and minor puppy disorders mention diarrhea as a symptom, making it difficult for owners to know what is severe and what isn’t.

Dehydration Dangers in Puppies

When puppies get diarrhea, they are at risk of quickly becoming dehydrated. They can quickly succumb to malnutrition and electrolyte imbalance.  If your dog excretes soft stools that are mushy and hard to pick up, this condition is considered diarrhea.

What Causes Diarrhea in Puppies?

Although many factors may cause diarrhea in puppies, these are the seven common ones that you need to be aware of:

  1. Diet change or food intolerance
  2. Bacterial infections
  3. Viral infection
  4. Ingestion of garbage, toxins, or foreign objects
  5. Parasitic infections
  6. Stress
  7. Inflammatory Bowel Disease

Diet Changes or Food Intolerance

For various reasons, you may want to change your dog’s food.

It might be that your veterinarian advised a higher-quality brand of food or that your local supermarket was running out of your dog’s typical kibble.

Unfortunately, a sudden change in nutrition can cause diarrhea in pups. Dogs need time to adjust to a new diet. This means gradually mixing new food with the old food. After about a week or two, your puppy should be ready to make the full switch.

In some cases, a puppy may simply have a food intolerance which can cause your puppy to have diarrhea.

Transition to New Puppy Food

When transitioning your dog’s chow from one type to another, begin by mixing the two and then gradually reducing the amount of the first one.

Consider temporarily offering your dog a bland diet to help cure your pup’s loose stools back to normal. A bland diet would include things like white rice and boiled hamburger without additional salt, pepper, or seasonings.

Your veterinarian can help you regulate your dog’s diet and treat her diarrhea if you feel she is intolerant or sensitive to certain foods.

four dogs with a blue background

Bacterial Infection

Compared to adult dogs, puppies have more sensitive immune systems, making them more vulnerable. Examples of bacterial infection include:


Campylobacter is a bacterial infection that may induce vomiting and diarrhea in both humans and dogs.

Raw meals, feces, and water are the most common sources of infection for dogs. Many other varieties of campylobacter germs may be present in regular dog feces, so just because your dog has Campylobacter doesn’t mean that it’s the source of her symptoms.


Raw or expired meat or contaminated feces are the most causes of salmonella poisoning in dogs.

Dog salmonella infections are rare but can be life-threatening and require hospitalization and medication if they occur. The salmonella strains that dogs carry can infect people in the same home even if they exhibit no symptoms, so it’s essential to watch them.


Clostridium perfringens type A in healthy dogs is a common form of bacterium that seldom causes any harm.

Enterotoxins (a toxin that targets the gut) produced by certain strains can induce bloody diarrhea, typically accompanied by mucus.

The bacteria produce these toxins in reaction to triggers such as antibiotic treatment, unexpected dietary changes, or infection with another bug.

Viral Infections

Unvaccinated puppies are susceptible to parvovirus, coronavirus, and distemper virus, all of which cause severe diarrhea that can lead to death.

Parvovirus type 2 (CPV-2)

Symptoms include:

  • Vomiting
  • Watery diarrhea
  • Lethargy

It’s the severity of the vomiting and diarrhea that make these viruses life-threatening. In fact, it’s often the dehydration caused by the illness that proves fatal.

It is a good idea to include immunization against parvovirus into your veterinarian’s vaccination program as soon as it is recommended. Healthy puppies can be vaccinated against parvo at six, eight, and 12 weeks of age.

The presence of virus particles in your dog’s stool can be used to diagnose parvovirus. Only an infected dog or recently vaccinated dog will have these particles.

Because of this, it is a pretty accurate method of diagnosing a parvovirus infection in dogs exhibiting parvovirus-like symptoms.

There is no cure for parvo. Puppies who contract the virus require supportive care, such as intravenous fluids to improve their chances of survival.

Canine coronavirus (CCoV)

This is a highly contagious intestinal illness that can affect adult dogs and puppies. Puppies (like all dogs) love to sniff and taste everything around them. Unfortunately, that leaves them vulnerable to viral infections.

The canine coronavirus can infect dogs who come in oral contact with contaminated feces. A dog can also contract the disease by eating from contaminated bowls or coming into close contact with an infected dog.

Canine coronavirus usually is short-lived. However, it can cause intense gastrointestinal pain in infected dogs.

For the record: Canine coronavirus (CCTV) causes gastrointestinal disorders in dogs and is not the same virus as SARS-CoV-2, which induces the new coronavirus (COVID-19).

Canine distemper virus (CDV)

Canine distemper is an infectious and deadly illness. It affects the:

  • Respiratory tract
  • Gastrointestinal tract
  • Neurological systems of puppies.

A dog or wild animal’s respiratory secretions can carry the virus, which is then breathed into the lungs of puppies and dogs. Unvaccinated pups and dogs are more susceptible.

Dietary Indiscretion in Puppies

Young dogs generally eat items they aren’t meant to. This is what we mean by a “dietary indiscretion”.

If your puppy can get her paws on anything, he’ll probably attempt to eat it, regardless of whether it’s garbage or hazardous.

Consuming waste (table scraps included), can induce diarrhea in puppies or cause intestinal blockage that require medical attention.

Toxins and poisons can also cause acute diarrhea. If you have any reason to believe your puppy has eaten something toxic,schedule a vet visit for immediate medical attention.

Parasites in Puppies

Parasites are organisms that survive on a host at the expense of the host’s health. Fleas and ticks are a couple of examples. Fleas can be swallowed if a puppy is putting his/her mouth on dead rodents or eating grass. Ticks are endemic in some areas and can easily be scooped up in tall grass. Both can cause serious health conditions.

Parasites exist in many forms. There are some you can see to those and others that are only visible through a microscope.

The one similarity they all share is that they induce varied intensities of health complications depending on the level of infestation. Intestinal parasites generally penetrate and cling onto the intestinal walls causing gastrointestinal symptoms such as vomiting and diarrhea.

If you suspect that parasites are causing your dog’s diarrhea, a veterinarian appointment is necessary.

Intestinal parasites can be categorized accordingly:

Intestinal worms or helminthic parasites

These parasites infect the mucosal lining of the intestinal tract where they take up residence.

Because of their strong bond with their host, they thrive by sucking nutrients from it

Diarrhea occurs due to the inflammatory reaction along the intestinal wall. Examples of these parasites include:

  • Roundworms
  • Hookworms
  • Tapeworms
  • Whipworms.

Protozoal parasites

These single-celled organisms infest dogs’ gastrointestinal tract and are known as “opportunistic” infections. You may not even know your dog has this infection because there are no signs and symptoms.

You only realize something may be wrong when the dog’s immune system is affected by another health problem.

Its effects are seen when a dog becomes immunocompromised, causing dormant protozoal parasites to multiply rapidly. This causes the infected dog to experiene excruciating pain and vomiting.

Pain relief drugs can be given to the dog to reduce suffering though it is also necessary to consider the side effects. Giardia and coccidial parasites like Isospora are two examples of protozoan parasites in dogs.

Four small pictures of dogs with a red background


Your puppy is always meeting new people and discovering new things.  Simply adapting to your household’s routine might cause stress-related diarrhea. Puppies may experience stress from things we never considered including:

  • Loud noises in the home
  • Frequent visitors (strangers to the puppy)
  • Missing siblings
  • Missing mommy
  • Separation anxiety
  • A sudden change in atmosphere like a move to a new home

Stress may compromise a dog’s immune system. When that happens, it leads to inflammation throughout the body. This then can lead to an overgrowth of bacteria in their intestines. The result? Diarrhea. In some cases, it can also lead to something known as stress colitis.

To determine whether diarrhea in your puppy was caused by stress, the vet will obtain a stool sample and perform fecal testing to determine if parasites are present.

A diagnosis of stress colitis could be made if the veterinarian discovers:

  • Signs consistent with acute colitis
  • A history of recent stressful evens (time in a boarding facility, kennel, sudden move, etc.)
  • Parasites not found in the fecal sample

Inflammatory Bowel Disease

IBD is more of a syndrome than a medical condition.

Chronic intestinal irritation is thought to cause vomiting, diarrhea, and potentially lack of appetite. The dog may lose weight if he has been vomiting or has had diarrhea, but this is normal.

IBD can affect any region of the digestive gastrointestinal (GI) system, although the stomach
and/or the intestines are the most usually affected.

In cases when the stomach is affected, your dog will experience vomiting as a symptom.

If the intestines are affected, the dog will experience diarrhea.

Both vomiting and diarrhea can develop when both your dog’s stomach and intestines are affected. If IBD persists, weight loss and loss of appetite start to appear. However, dogs that cannot process and absorb what they consume might develop an insatiable hunger as a result.

The exact cause of IBD is unknown. It seems that several factors could cause the condition.

Whatever the reason, the outcome is that inflammatory cells infiltrate the gut lining.

The digestive tract then experiences allergic reactions. This could be caused by things like parasitic or bacterial infection (for example, Salmonella, e Coli, or Giardia). It could also because from a reaction to specific proteins in their normal diet.

We thought you might be interested in related posts so we’ve hand-picked a few for you to look at. Check them out:

Are Acorns Poisonous to Dogs? 5 Signs of a Medical Emergency

Should Your Dog be Breathing So Fast? How to Assess your Dog’s Breath Rate

Pepto Bismol for Dogs – Be Careful

Signs of Dehydration in Puppies

The most important thing is whether or not your puppy is becoming severely hydrated. The cause of the problem can be addressed later. For now, check to see if your puppy has any of the following signs of dehydration:

Loss of Skin Elasticity

Gently pull the skin on the back of your dog’s neck near the shoulder blades. Let is go and watch what happens. If your dog is well hydrated, the skin will spring back in place. If not, the skin will take longer to slide back into place.

Check Gum Tissue

It’s a good idea to check your dog’s gums when he/she is healthy. In some breeds, it may be harder to tell the difference because of the natural color of the gums.

Gently press your finger tip on your dog’s gums. If they feel sticky or dry, your puppy could be dehydrated.

Capillary Refill Time

This can be tested while checking for dry and sticky gums. Press your finger gently on the dog’s gums and then remove your finger. If your dog is well hydrated, the color of the gums should quickly change from pale to pink.

If your dog is dehydrated, it will take longer for the gums to return to their normal color.

Diarrhea is Dangerous in Puppies

At the end of the day, it’s important to understand how dangerous diarrhea is in puppies. Any dog can succumb to dehydration quickly, but puppies are very much at risk. Never let diarrhea continue for more than 24 hours without seeing a veterinarian.

In some cases, you may want to contact a veterinarian even sooner. It’s much better to be safe than sorry in this case.

Remember that there are all kinds of reasons why your dog has diarrhea. Most of them are benign. But why take the chance? Contact your veterinarian to see if they think you should bring your puppy in or whether it’s safe to wait.

Put Your Worries to Rest

I know what it’s like to be really worried about my dog’s health. If there’s going to be a problem, it always seems to happen on a weekend or a holiday when getting in touch with the regular veterinarian isn’t easy.

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