My Dog Gets Diarrhea at Night – (Explained and Help)

When a friend relates to me that “my dog gets diarrhea at night” I always respond with a reassuring statement that a dog can have diarrhea for many possible reasons.

Among the most common causes of diarrhea in dogs are food allergies, dietary indiscretion, intestinal infections, intestinal parasites, infectious enteritis, inflammatory bowel disease (IBD), dietary indiscretions and simply eating too much one day or too fast!

Important Considerations about nighttime Diarrhea

It’s not uncommon for people to wake up after a noisy night and find their dog has left a mess on the floor. It can happen in the day too, but mostly at night it seems.

People usually put two and two together and assume their pup is getting sick or unwell somehow, but this may not be so.

There are actually several common reasons why dogs get diarrhea at night, especially if they’re eating something different that day or you’ve given them some human food, so read over the list below and see if anything applies.

It is naturally important to say that many dogs tend to experience problems with their bowels and gastrointestinal system.

Diseases such as Colitis and IBD are very common to cause your dog to lose control of the bowels. These can also cause the dog to vomit. Diarrhea and vomiting in a canine is not a good sign, so it is important that you take your pooch to the veterinarian immediately.

Most Common Causes

1. Quick changes in diet

A dog that has recently had a change in diet or has been fed with a new food is at a higher risk of being affected by diarrhea in the night.

On the other hand, if your dog has been fed on the same type of food for some time, he/she might not be susceptible to diarrhea during this time.

2. Stress 

Stress can not only lead to diarrhea in the night, but it can also lead to gastrointestinal illnesses such as ulcers, indigestion and even stomach ulcers as well!

Animals can become very stressed by the loud, mysterious noises that they hear at night. They can also be frightened by any number of things, such as a new family member or visitor to your home. With so much more going on, it’s very common for them to become stressed and have problems with their digestive system.

3. Giving your pet human food

Giving your dog or cat human food is in itself not dangerous. However, if they do not get used to it, they can be prone to getting diarrhea in the night when they have been given a new type of food.

4. Drinking too much water

Drinking too much water can lead to a number of diseases and disorders for humans as well as for dogs and cats.

When their system has become used to having less water, this can cause diarrhea in the night.

On the other hand, as stated above, drinking too little water may also cause diarrhea in the night.

5. Too much exercise before bed

Exercising your pet in the day can help to reduce strain and stress. On the other hand, exercising your pet before bedtime can also lead to diarrhea in the night.

Even if you have exercised your pet, they can still get diarrhea in the night when they have been under too much stress during this time.

6. Diarrhea caused by a parasite infection

One cause of diarrhea that has been noted is intestinal parasites or worms (worms or tapeworms). T

his may give you a chance to catch it early and treat it with medication before it causes too many problems for the rest of your pet’s life.

7. Licking itchy, irritated skin

Your pet has a protective layer on the outer layer of its skin which is called the epidermis.

This keeps them protected from external factors that can cause irritation and itching. When this is damaged and starts to get infected, a number of things can occur which include diarrhea in the night.

Normally, once your pet’s body has had time to repair itself, this will stop and you won’t need to worry about it again.

8. Allergies to fleas, ticks and other insects

Pets are like humans! There are insects that can bite their skins during the day or when they sleep at night.

These types of insects can cause a lot of different problems in your pet’s health as well as their system.

Usually, they will die off naturally if your pet is left untreated. However, they can result in diarrhea. On the other hand, if they are not on medication to control them, then these types of infections may be harder to manage and you should consult with your vet as soon as possible.

9. Consumption of oral antibiotics

In most cases, when you visit your vet when your pet has been diagnosed with an infection, it has already passed and the medicines prescribed will help to reduce any inflammation caused by it.

Unfortunately, as with humans, antibiotics can create both constipation and diarrea.

10. Re-infection after being cured or when their immune system is weakened

There are a lot of different types of skin parasites that exist all over the world.

Sometimes, pets may get re-infected due to contact with these types of parasites during grooming or playing with others that have them.

These kinds of parasites can be highly contagious and normally cause a lot of irritation where they live on your pet’s skin for the time they are there before you notice anything.

This type of parasite may also have caused diarrhea in the night in the past.

12. Exposure to poisons or dangerous chemicals

There are a number of different types of poisons and chemicals that are found in our surrounding environment.

In a lot of cases, these types of things are not even really harmful to humans, animals and birds when exposed to them in small amounts.

However, if your pet is exposed to some of these types of chemicals on a regular basis, it can lead to diarrhea both during the day and in the night.

This may also apply to an environment that has been polluted by fertilizers or other substances used in everyday life that may leak into the ground and contaminate water sources which will lead to different diseases which can include diarrhea.

13. A change of water supply

Some pets are sensitive to the water supply they drink and it may cause them diarrhea.

Changing the water supply or how it is purified can also lead to diarrhea in the night.

14. Overfeeding

Overfeeding is another major cause of diarrhea in the night.

Overfeeding can cause obesity which obviously will lead to diarrhea! Either give your pet only what they need or reduce their food by a little so that they will be able to eat more normally.

Normally, once the diet has been modified, diarrhea in the night should no longer be a problem.

15. Giving your pet too much exercise

Excessive exercise can lead to an increased amount of stress and strain on them and extra calories inside their body acids can build up causing diarrhea in the night.

You should never overdo your pet during this time as this is an unnecessary risk.

16. Taking medication that can cause diarrhea

There are a number of different medications that can cause diarrhea in the night.

Some of these include antibiotics and steroids. These are only given to your pets under medical supervision due to their potential for causing problems with the rest of your pet’s body and system.

17. Intense physical activity

Intense physical activity can lead to a lot of different health problems and one of these is diarrhea in the night.

Usually, when your pet has been too active during the night, this will cause them to consume excess calories which could lead them to becoming ill.

Normally, you should stay away from activities that may cause stress or strain on your pet’s body as much as possible.

18. Obesity

Obesity is another reason for an excessive strain on your pet’s body potentially causing diarrhea in the night.

Obesity can lead to a number of different health problems which can include heart disease, diabetes and parasites. You should always keep your pets on a diet so that they don’t suffer from obesity.

19. Allergy to the food, medicines or chemicals that they are being fed

Some types of food can cause an allergic reaction in your pet’s body causing diarrhea in the night.

If you suspect this is the case, you should consult with your vet to find out what has been causing this allergic reaction and try another one if it persists.

20. Stomach problems or ulcers

Stomach problems or ulcers can also be caused by some medications and they may cause diarrhea in the night.

This is more of a risk for older pets due to their weakened immune system due to age as well as hypothyroidism (an underactive thyroid gland).

21. Unbalanced diet

In some cases, an unbalanced diet can cause diarrhea in the night due to a lack of water-soluble vitamins and minerals.

Your pet needs water-soluble vitamins and minerals for their immune system to work as well as other body functions.

An unbalanced diet is not only caused by eating too much or too little; it can also be caused by eating food with ingredients that are hard for your pet’s body to digest or absorb completely.

This will lead to diarrhea in the night as well as other health problems such as allergies and infections like worms, fleas, ticks, skin problems and gastrointestinal problems.

22. Infections caused by bacteria and fungi

Infections that are caused by bacteria or fungi such as salmonella and E Coli can also cause diarrhea in the night.

Normally, your pet’s immune system should be able to fight off these problems but if they have had an unbalanced diet or eaten some type of food that is hard for their bodies to digest; this will lead to an infection which will cause them to develop diarrhea in the night.

23. Laxative poisoning

Just like humans, pets can overdose on laxatives which can lead to diarrhea in the night.

This can be especially bad for them if they have ingested too much and they end up getting dehydrated as a result!

24. Toxoplasmosis

Toxoplasmosis is another cause of diarrhea in the night.

Toxoplasmosis is normally only seen in cats and it can be contracted by them by an infected rat or mouse.

It can also be contracted through contact with undercooked contaminated meat, exposure to infected cat faeces. The symptoms of toxoplasmosis include fever, listlessness, a swollen lymph node and diarrhea.

25. Worms

Worms can cause diarrhea in the night. This is normally due to roundworms, tapeworms, hookworms and whipworms. 

26. Cancer

Cancer is another problem that could cause diarrhea but this is more of a long-term problem.

If you notice a type of colored stool, like red or black stools, you should consult with your vet about them immediately as it could be a sign of internal bleeding from a tumor or some other type of cancerous growth that may need treatment ASAP!

27. Pancreatitis

Pancreatitis is also known as pancreatic insufficiency. This can cause diarrhea in the night in older pets.

Pancreatitis means there has been inflammation of your pet’s pancreas. It is normally caused by trauma or toxic materials to their body as well as some infections.

28. Yeast infection

Yeast infections are another cause of diarrhea in the night because yeast normally lives inside your pet’s gastrointestinal tract.

Yeast infections can be caused by antibiotics, an unbalanced diet or a stomach virus. If you suspect that your pet has a yeast infection, consult with your vet about it immediately as this can lead to them developing diarrhea in the night.

In Conclusion

There are many causes for diarrhea in the night, some of which are more common than others.

If your pet has been experiencing repeated cases of diarrhea, it is best to consult with your vet about them and find out why they may be happening.  

Diarrhea in the night can be a life-threatening situation that is more of a risk for older pets due to their weakened immune system and their age. If it happens more than once in a 24 hour period, you should seek medical attention immediately.


American Kennel Club

VCA Animal Hospital



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