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Puppy Diarrhea At Night? Here Are 7 Most Common Causes

Puppy Diarrhea At Night? Here Are 7 Most Common Causes

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When it comes to puppies, diarrhea is a widespread and relatively common occurrence. If you do a quick search on the web, you might be bombarded with an endless supply of puppy diseases, infections, and conditions whose only warning sign may be puppy diarrhea at night.

If nighttime diarrhea has recently become your puppy’s favorite sport, the first thing you should do is take a deep breath and calm down. Fortunately for dog owners, nighttime diarrhea in puppies is usually caused by something relatively benign.

Typically, puppy diarrhea at night is linked to one of several major causes. However, each of these causes is relatively harmless as long as they are treated accordingly.

Your young puppy might be experiencing diarrhea at night as a result of microbial infection, bowel inflammation, sudden change in diet, garbage toxicosis arising from dietary indiscretion, or even leaky gut.

In addition, stress, fear, anxiety, and allergies can also cause nighttime dog diarrhea. When one or several of these conditions occur, your puppy may experience discomfort such as that its sleep quality and quality of life are disturbed.

In this article, we will go over the most common causes of puppy nighttime diarrhea. Hopefully, by the end of our puppy diarrhea at night guide, you will be able to recognize the symptoms of each health condition that might lead to your dog defecating at night.

1. Why does my puppy have diarrhea at night? Parasites

close shot puppy lying in dark

Parasites are the number one cause of puppy diarrhea at night. This is actually to be expected since your young pooch is just starting to come into a relationship with its surroundings.

Unlike humans, who interact with their surroundings primarily through the sense of sight and touch, our canine companions primarily use the sense of taste and smell.

There are a multitude of parasites your young furry explorer can come into contact with by simply roaming around the yard. It can come from sniffing or licking a dead squirrel or some other critter that found its way onto your property and died there.

Bear in mind that parasites can be found in young, adult, and even senior canines, but puppies are more prone to catching them as they are much more eager to explore their brand-new environment.

Typical intestinal parasites found in puppies include giardia, hookworms, whipworms, roundworms, coccidia, tapeworms, and many others. Because of this, it is very important to deworm your pooch regularly to prevent parasites from doing any harm.


Giardia (specifically Giardia duodenalis, Giardia lamblia, and Giardia intestinalis) is one of the most common causes of diarrhea in puppies.

Puppies under six months of age are the most vulnerable to giardia, and they usually encounter this parasite in early winter or late fall, just as the temperature begins to drop. This nasty parasite will wait patiently in cold, dark puddles and other stagnant bodies of water to be picked up by an unsuspecting dog.

One of the scariest things about giardia is that human beings can get it as well. Taking care of your furry friend with nighttime diarrhea can be a handful, and you don’t want to have to take care of yourself at the same time.

Fortunately, treating giardia is relatively easy as long as you get your pet to a veterinarian. Once your puppy is diagnosed with giardia, you should keep your house sanitized so that it doesn’t pass the parasite on to you.


The second most common puppy parasite is roundworms (also known as Toxascaris canis and Toxascaris leonina), which is an affliction almost every canine will encounter during its lifetime.

The vast majority of pups who experience roundworms will do so during puppyhood. If not treated, this parasite can be quite serious, leading to loss of appetite and malnourishment in adolescent and senior dogs.

In most cases, roundworms are passed on from the mother to her offspring. Fortunately, it is highly treatable.


Hookworms, which is actually an umbrella term for three different parasites, are very common in young dogs. These parasites get their name from the hooks in their mouths that they use to attach themselves to the wall of your dog’s gastrointestinal tract.

Though almost impossible to spot with the naked eye, if left untreated, these worms can suck out massive amounts of blood from your puppy’s body, leading to severe anemia (iron deficiency).

In most cases, these worms find their way into a dog’s system through larvae ingested from their surroundings, or they are passed on by the dog’s mother.

2. Puppy with diarrhea at night – stress or phobias

dog pooping in dark

Another common cause of puppy diarrhea at night is stress. This may come as a surprise since all you see is a playful, loving, and bouncy little puppy, but stress is extremely common in young canines.

The world is a vast place, and it takes a long time, even a lifetime, for your pooch to adjust to it. This is not only the case with dogs but humans as well!

If you’ve recently made significant lifestyle changes that have affected your puppy in any way, it could induce a lot of stress and lead to nighttime diarrhea. Also, some dog breeds are prone to separation anxiety if left alone for long periods.

Puppies, like children, and most adult human beings, crave stability. Because of this, your puppy will thrive in a stable environment and might experience health and behavioral issues otherwise.

In addition to stress, puppy diarrhea at night might be caused by certain phobias. Some dogs are fearful of abrupt loud noises such as thunder or yelling. Others are more reserved and often very shy in the presence of strangers or new owners. These situations could be triggers for nighttime diarrhea in your puppy.

3. Puppy diarrhea at night only – infections

Canines of all life stages come in contact with many viruses and bacteria on a daily basis. But, almost all of these viruses and bacteria are easily dealt with by an adult dog’s highly efficient immune system.

Puppies, on the other hand, have a hard time getting rid of these viruses and bacteria from their bodies. Virus or bacterial infection can be one of the causes of puppy diarrhea at night.

Bacterial infection

For a puppy, there is no hiding from harmful bacteria that may be hazardous to its delicate body. One of the most common ways for canines to pick up a bacterial infection is through contact with rotten meat or birds.

Bordetella, Salmonella, and E. Coli are just some of the infections that can threaten the overall well-being of your young furry friend. All of the bacterial infections we mentioned are very dangerous and must be dealt with by a vet as soon as possible.

The usual symptoms of a bacterial infection are vomiting, loss of appetite, fever, and bloody stool. If you notice any or all of these symptoms, make sure to immediately take your pooch to a vet.

Viral infection

owner checking dogs temperature

Viral infections can be a fatal threat to your canine companion. For instance, canine distemper is one viral infection that can cause puppy diarrhea at night, and the prognosis for this condition is unfortunately bleak.

A common way for this infection to spread is through contact with wild animals. Raccoons are known as one of the most common carriers of the virus and can carry it in their system for months.

According to the American Veterinary Medical Association (AVMA), canines infected with this viral infection have the following symptoms:

• runny nose

• fever

• coughing

• vomiting

• diarrhea

• seizures

• snotty nose

• paralysis

If your puppy or adult dog is experiencing some of these symptoms, it doesn’t necessarily mean that it is infected with canine distemper, but nonetheless, you should seek out professional help.

However, if your furry friend is experiencing all of these symptoms, the situation is dire, and you should call your vet immediately.

4. Puppy diarrhea only at night – dietary indiscretion

dog standing in dark looking at camera

Dietary indiscretion refers to a change in your dog’s feeding regime leading to your dog being less picky about the kind of food they eat.

In this case, your four-legged friend may consume substances that their body cannot tolerate, including table scraps, carcasses, rocks, toxic plants, raw or spoiled food, garbage, feces, and so on.

Furthermore, dietary indiscretion may be due to a change in your dog’s behavior (self-inflicted), in which case you can expect it to eat garbage, feces, carcasses, and other materials on purpose.

However, the most common reason for dietary indiscretion is the reckless behavior of the dog’s owner. Some owners feed their furry friends inappropriate diets, ranging from unhealthy dog food and table scraps to leftovers from the kitchen.

Regardless of the reason behind it, dietary indiscretion allows foreign objects like toxic substances and bacteria to find their way into the bloodstream, causing a condition vets termed “garbage gut” or “garbage toxicosis.”

Dietary indiscretion is one of the common causes of puppy diarrhea at night and may be accompanied by symptoms such as lethargy, loss of appetite, and vomiting.

5. Puppy has diarrhea at night – an abrupt change in diet

Switching your dog’s usual kibble is not something to jump into without considering all of the side effects. When you decide to change your dog’s diet, you should make the transition as slow as possible, with the recommended period being around two weeks.

As a responsible owner, you should keep in mind that a sudden change in your furry friend’s diet can cause problems to its digestive system, resulting in vomiting and, you guessed it, nighttime diarrhea.

Licensed veterinarians suggest that owners begin the diet switch by adding a small amount of the new food to their dog’s regular meals. Once the dog gets used to the taste of the new kibble, the owner should increase the amount gradually each day until the transition is safely completed.

During a diet change, it is vital to monitor your dog’s health to ensure that the transition is going smoothly. This is especially important if you have adopted a puppy or got a puppy for free since these pups are often fed low-quality food. While it seems like a great idea to feed your new puppy high-quality food from the start, you may want to give it some time to adapt to the new diet.

6. Puppy gets diarrhea at night – inflammatory bowel disease

owner cleaning floor after dog

Inflammatory bowel disease (IBD) is a condition where an abnormal response from a dog’s immune system causes the intestinal tract to become inflamed. This affects the absorption and digestion of nutrients, and if left untreated, can be detrimental to your dog’s health.

Veterinarians are not completely sure what causes inflammatory bowel disease in canines, but certain factors may lead to this chronic medical condition. IBD can also be a sign of a more serious underlying health condition like parasites, bacteria or viral infections, or overactivity of the immune system.

Inflammatory bowel disease is known to induce nighttime diarrhea and bloody streaks in a dog’s stool. It is something you should be aware of if your puppy or adult dog is diagnosed with this chronic disorder.

7. Why does my puppy have loose stools at night? Foods and drugs

Humans can develop severe allergic reactions to all sorts of foods and drugs. Unfortunately, our canine companions are not so different from us and can suffer from food or drug-related allergies as well. These allergies are mainly associated with genes, and some breeds of dogs are genetically more prone to developing them than others.

An allergic reaction is an abnormal response of the immune system to substances the body doesn’t recognize and treats as foreign objects (allergens). When first exposed to an allergen, the immune system usually doesn’t react right away but becomes sensitized. So, each subsequent contact with the same allergen can provoke a strong reaction from the immune system known as anaphylaxis.

The most common foods that trigger allergic reactions in dogs are beef, eggs, corn, dairy, and chicken. However, dogs can be allergic to many more substances, and allergic reactions can also lead to gastrointestinal problems such as vomiting and diarrhea.

Another thing that can cause puppy diarrhea in the middle of the night is food intolerance. However, food intolerance is slightly different from food allergies because it does not involve any response from the immune system. It simply means that your pooch cannot properly digest certain food materials. To ensure the well-being of your beloved furball, make sure to keep it away from any known allergens, be it drugs or food.

Puppy having diarrhea at night – what to do?

dog sleeping wrapped up in blanket

In general, diarrhea is not a serious condition, and home care is the most common solution. If your puppy has no behavioral issues and nighttime diarrhea has only happened once, the chances are that your vet will recommend home care.

However, there are situations where puppy diarrhea at night might be a sign of a more serious health issue. Here are a few things you should keep an eye out for to determine whether you have a more severe problem on your hands:

• Stool – A puppy’s stool should be chocolate brown in color. A green-colored stool may indicate excessive grass consumption or underlying health concerns. If your dog’s poop is black and tar-like, brown with white flake-like material, grey and greasy, or brown with red streaks, a serious issue is likely happening in your furry friend’s body, and you should contact a vet immediately.

• Other symptoms – If the nighttime diarrhea is accompanied by white gums, fever, vomiting, discomfort, lethargy, or pain, the chances are that an upset stomach is the least of your worries.

• Ingestion of toxic substances – If you are sure that your pooch swallowed something it wasn’t supposed to (like Roundup weedkiller or rat poison), take your dog to a veterinarian immediately.

• Long duration – Normally, puppy diarrhea at night should not exceed three days. So, if your puppy has trouble with loose stools in the middle of the night for more than three days, you should take it to a vet for an exam.

• Dehydration – Severe and long-lasting diarrhea can cause dehydration and is considered a medical emergency. In the case of dehydration, you should take your canine companion to the vet for proper treatment.

Puppy with diarrhea at night – home treatment

black dog looking up waiting for food

As long as the cause of the diarrhea is not something we mentioned in the last section, home care can be an effective treatment. First and foremost, you need to keep in mind that diarrhea is extremely dehydrating, so make sure you provide your puppy with lots of fresh, clean water as its primary treatment.

Apart from providing your dog with lots of water, here are some other steps you can take:

Stop giving your pup food

It might seem counterintuitive since your pooch is probably hungry from pooping everything out, but not feeding your pup is the way to go. Fast your dog for between twelve and twenty-four hours, depending on its age and size.

Puppies will usually lack the capacity to fast for a longer time, so keep it closer to twelve hours. The main reason for not giving your pup food is to allow the gastrointestinal tract to rest and recuperate. Also, remember to provide your pup with lots of water during this period.

Switch to a bland diet

Similar to how humans tend to eat plain toast when we have diarrhea or vomiting problems, bland puppy food is a great home remedy for pups with stomach problems.

A bland diet should consist of a protein source (like shredded chicken breasts or beef mince) and a low-fiber starchy food (like plain cooked white rice). You can also include rice water, shredded turkey, or cottage cheese as a protein source. The meal size of the bland diet should be equal to the meal size of their normal diet.

Gradually transition to their normal food

After a day or two of bland diets, try to slowly reintroduce your puppy’s normal diet. The process is similar to introducing new foods into your dog’s regular dish.

Start by mixing half of both the regular food and the bland diet you’ve been feeding your pup and slowly tip the scale in favor of their normal diet until the transition is complete.

Introduce probiotics

If your dog is experiencing loose stools during the night, the chances are that the normal microbiome of its gut has been disrupted. This means that the proper digestion and absorption of nutrients are hindered.

This is where probiotics can come in handy. Probiotics are known to help with gastrointestinal problems, including inflammatory bowel disease and diarrhea. They are packed with healthy bacteria such as Bifidobacterium and Lactobacillus, which are normally found in the gut microbiome. Also, probiotics are known to improve and nourish the community of healthy bacteria in the gut while boosting the immune system at the same time.

Serve your pup some peppermint tea

Another great home remedy for loose stools in the middle of the night is giving your doggy a calibrated amount of peppermint tea.

Peppermint is effective in dealing with GI problems such as flatulence, cramps, and vomiting. The recommended amount of peppermint is 25mg of dried herb per pound of body weight twice a day.

My puppy has diarrhea at night – how to prevent it?

dog lying on his bed at night

Now that we know how to treat nighttime diarrhea in canines, the next thing to figure out is how to prevent it. Fortunately, a few basic remedies can greatly reduce the chances of puppy diarrhea at night.

1. Transition new foods slowly

Puppies have delicate stomachs, and abruptly changing their kibble can lead to all sorts of health and behavioral problems. Because of this, be sure to make the transition from one food to another as slowly as possible.

2. Vaccinations

Always keep in mind that vaccines save lives. As we’ve seen above, one of the scariest causes of puppy diarrhea at night is viral infections. Fortunately, the most harmful canine viruses are totally preventable!

Make sure your four-legged furball is fully vaccinated, especially when you take it on camping trips, playdates, or doggy daycare centers. One thing to note is that vaccines can cause diarrhea in puppies as a side effect. However, this is normal and usually resolves itself in a day or two.

3. Long-term confinement

With short-term confinement, the puppy is left without supervision and no recourse to use the bathroom. On the other hand, with long-term confinement, the puppy can be left without supervision for longer periods as a bathroom is included in its confinement space.

However, you should be careful when selecting the area for long-term confinement. For instance, if you wish to keep your puppy outdoors, you either need to make sure there are absolutely no hazardous substances for your puppy to ingest or to monitor it constantly. This has proven to be very difficult for most dog owners as viruses and bacteria can be found in the soil, toxic waste can find its way into your yard from the sky, and some backyards are home to vegetables or fruits that are toxic to dogs.

Because of all this, some pet owners use kenneling as a solution. However, while kennels are excellent as a short-term confinement tool, keeping your pup kenneled for long periods is considered inhumane.

4. Sanitation

If you are keeping your furry friend kenneled alone or with other dogs, you must keep the kennel highly sanitized. An unclean kennel is a perfect place for diseases, viral infections, and bacterial colonies to settle in and breed.

If your pooch is sharing a kennel with other furry friends, make sure to wipe it down every day with strong sanitizers. This will help prevent bacterial and viral spread if it occurs.

Final thoughts

puppy sleeping in arms of owner

Photo from:@pet_house_22

By now, you should have a firm grasp on the most common causes of puppy diarrhea at night. But, you should also know that completely preventing diarrhea is not always possible.

With that said, dietary management will reduce the likelihood of toxicities and infections that can lead to diarrhea. Simply put, ensuring proper hygiene in your pet food handling and gradually changing your pet’s diet will preserve the health of your four-legged companion.

Through regular observation of your dog’s stool sample, you will easily notice when the consistency or color suddenly changes from normal.

But, as with all things, it is better to be safe than sorry. So, if your pooch is having loose stools at night, you should contact your local vet to make sure there are no serious health issues hiding beneath the surface.