Old dog diarrhea at night

What would be the main causes of nocturnal diarrhea in elderly dogs? Elderly dogs can have several degenerative problems and illnesses that can result in diarrhea symptoms. In this post  we are going to talk about the main causes of diarrhea in elderly dogs and what should be done to prevent the worsening of the animal’s health.

Old dog diarrhea at night

Nocturnal diarrhea in elderly dogs can happen for several reasons such as:

  • Degenerative diseases
  • Tumors / Cancer
  • Infectious diseases;
  • Food allergies;
  • Food poisoning;
  • Sudden change in diet.

Degenerative diseases

Elderly dogs can present some organ degeneration. The most common degeneration is renal failure. More advanced renal failure can lead to several damages to the dogs health that can result in apathy, vomiting, loss of appetite and even diarrhea.

Elderly dogs must receive adequate treatment for kidney diseases to avoid complications that can lead to the death of animals. That is why it is recommended to increase the frequency of visits to the veterinarian for elderly dogs.

Tumors / Cancer

Cancers and tumors in elderly dogs are common in many animals. Therefore, the worsening of the animal’s health must be prevented with periodic consultations and check-ups with the veterinarian.

Gastrointestinal tumors or metastases from other tumors can lead to increased gastrointestinal motility resulting in diarrhea. Some chemotherapy treatments for tumors can also lead to diarrhea in some dogs.

Infectious diseases

Some diseases caused by viruses, parasites and bacteria can lead to an imbalance in the dog’s microbiota, leading to diarrhea.

  • The main viruses that can lead to diarrhea in dogs are canine distemper virus, coronavirus and rotavirus.

In general, the viruses replicate in the gastrointestinal mucosa cells and can lead to lesions, thus reducing the absorption of liquids and nutrients that are excreted in the feces that become more liquid. Some virus diseases can lead to blood in the dog’s feces.

When leading to mucosal injury, changes in the gastrointestinal microbiota can also occur, which further worsens diarrhea in dogs. Viral diarrhea can be prevented by vaccines. In general, these diseases have no treatment for dogs, but treatments for secondary changes can be prescribed.

  • About the diseases caused by bacteria, Escherichia coli, Salmonella and Shigella are the most frequent bacteria to lead to diarrhea in dogs. The canine gastrointestinal microbiota is mostly made up of bacteria.

When foreign bacteria start to replicate in the gastrointestinal tract, the microbiota try to avoid this replication. However, the excess of foreign bacteria causes a dysregulation of the microbiota, reducing the absorption of nutrients, leading to diarrhea.

The treatment for bacterial diarrhea may involve the use of some antibiotics and the reconstitution of healthy microbiota for the intestine of dogs.

  • Parasitic diarrhea can occur mainly due to parasites such as Giardia, Ancylostoma caninum, Toxocara canis and Dipylidium sp. These parasites have different cycles, but they all affect the functioning of the gastrointestinal system leading to diarrhea.

Parasitic diseases can be avoided through periodic feces laboratorial examinations and the use of oral antiparasitic drugs. Treatment consists of antiparasitic drugs, microbiota replacement and nutrient supplements when necessary.

Food allergies

Food allergies can affect some breeds of dogs, it can be a hereditary trait, so you should avoid breeding these dogs.

Dogs with food allergies should see a veterinary gastroenterologist to find out the cause of the allergies through testing. After the diagnosis, the dog should avoid consuming the food that causes the allergy.

For some dogs it may be necessary to consult with a veterinary nutritionist so that a balanced natural diet is prescribed. For other dogs it may also be necessary to use specific industrial diets for the gastrointestinal tract. Thus, avoiding allergies that lead to diarrhea.

Food poisoning

Consumption of spoiled or contaminated food can carry toxins into the gastrointestinal tract. These toxins can unbalance the microbiota leading to diarrhea.

Intoxicated animals should see a veterinarian. In many cases, dogs can receive fluid therapy to reduce the effects of toxicants. Procedures such as gastric lavage can be performed in some situations.

Treatment includes replacement of fluids, gastrointestinal microbiota, and nutrients. Some dogs can become dehydrated quickly due to increased symptoms such as vomiting and diarrhea. Emergency care by a veterinarian is required.

Sudden change in diet

Changing the dog’s diet without an adaptation can led to changes in the composition of the dogs’ microbiota, which can result in diarrhea.

Changing the dog’s diet should be done progressively as shown below:

  • 1st and 2nd days: 75% Old food + 25% New diet.
  • 3rd and 4th days: 50% Old food + 50% New diet.
  • 5th and 6th days: 25% Old food + 75% New diet.
  • 7th day onwards: 100% New diet.

What to do when the elderly dog has diarrhea?

Old dogs’ diarrhea can be symptoms of various diseases and can have many causes. That’s why dogs with constant diarrhea should be taken to the veterinarian for a consultation.

In general, elderly dogs with diarrhea can lose a lot of fluid and electrolytes that can lead to dehydration. And dehydration can kill the dog. Therefore, the consumption of liquids and balanced foods by the dog should be encouraged.

The treatment of diarrhea may vary according to the cause, and it is important not to administer any medication to dogs without a veterinarian prescription.

Diarrhea prevention can happen with the provision of adequate food for dogs. Constant visits to the veterinarian for vaccinations and exams to assess whether the animal has any worms.


Elderly dogs need a lot of attention and more frequent visits to the vet. With age, several health problems can lead to altered immunity and the appearance of various diseases that can result in diarrhea in elderly dogs. These diarrheas can happen at night and even during the day. Dogs must be treated properly to avoid worsening health and even dog death.

Frequently Asked Questions (FAQs): Yogurt for dog diarrhea

What to give a dog when he has diarrhea?

It is recommended to stimulate the dog’s consumption of liquids, avoiding dehydration. Fresh water can be offered, or even a physiological solution. A good option is to offer your dog coconut water, as it is rich in potassium and is appreciated for the dog’s taste.

What to do when the dog has diarrhea?

The tutor should seek a veterinarian immediately. Since the loss of water and nutrients can lead the dog to dehydration and death.  

And with veterinary treatment, the animal tends to improve and go home healthy.

What foods are toxic for dogs?

Common foods that are highly toxic to dogs are:

  • Grapes and Raisins;
  • Xylitol;
  • Chocolate;
  • Tea;
  • Coffee;
  • Onions;
  • Garlic;
  • Alcohol.


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Macedo, H. T., Vendramini, T. H. A., Rentas, M. F., Risolia, L. W., Oba, P. M., Zafalon, R., … & Brunetto, M. A. CAPÍTULO X MICROBIOMA DE CÃES. Novos Desafios da Pesquisa em Nutrição e Produção Animal, 190.

Oliveira, J. C. V. D., Cian, D. M., Bettini, C. M., & Lazaretti, R. M. J. (2011). Agentes etiológicos que causam gastroenterite em cães com mais de um ano de idade no município de Maringá.

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