Great Dane Diarrhea And Not Eating: Causes + What To Do 

Great Dane diarrhea and not eating are symptoms that sometimes occur together. Loss of appetite or a dog not eating is a decrease in interest in food or a complete refusal to eat. It is an unusual dog behavior,  and raises concern especially when accompanied by other concerning symptoms such as diarrhea.

While diarrhea is common in Great Danes, it is important to understand what causes these two symptoms and when to seek veterinary care.

We outline the potential causes of Great Dane diarrhea and not eating, along with the associated symptoms and when to seek help. 

Here’s why Great Dane diarrhea and not eating occurs

Great Dane diarrhea itself can lead to loss of appetite and a Great Dane not eating. These symptoms  commonly occur together, and can be due to a number of illnesses and health issues which include diet change, illness, gastrointestinal infection, poisoning, stress, and medication side effects.  

Great Dane diarrhea and not eating or loss of appetite are symptoms of a condition, rather than conditions in themselves. 

great dane diarrhea and not eating

Causes of Great Dane diarrhea and not eating

A Great Dane not eating or loss of an appetite is a common symptom of a Great Dane suffering from diarrhea. A Great Dane may experience both diarrhea and not eating as a result of an underlying condition. 

The possible causes of Great Dane diarrhea and not eating are:

Underlying illness 

Diarrhea and not eating can be symptoms of a wide range of illnesses in Great Danes, including viral or bacterial infections, gastrointestinal disorders, and systemic diseases.

There are many factors that can cause a Great Dane to not eat when they are ill, which include pain, nausea, digestive problems, and emotional distress.

Pain due to an illness can cause a Great Dane to avoid eating or drinking. In addition to this, many illnesses can cause nausea which can make them feel too sick to eat.

Digestive problems due to illnesses such as vomiting or diarrhea can also lead to a lack of appetite and emotional distress experienced when they are ill can cause them to also lose their appetite.

Related: Great Dane throwing up: Causes, symptoms and management

Gastrointestinal infection

Gastrointestinal infection by bacteria, intestinal parasites, or viruses can cause Great Dane diarrhea and loss of appetite.

Gastrointestinal infections can cause a Great Dane to lose its appetite due to nausea, vomiting, diarrhea, and discomfort. These symptoms can lead to a loss of appetite in the dog.

Change in diet

A change in your Great Dane’s diet can cause diarrhea and refusal to eat due to food intolerance or allergy, an upset stomach, and stress.

This is because it takes time for your Great Dane’s stomach to adjust to the new food and a sudden change to a new food may cause diarrhea. 

Great Danes are also sensitive to changes in their routine and environment, and a sudden change in diet can be stressful. 

The stress can lead to digestive upset which causes diarrhea including other symptoms and a Great Dane not eating due to :

  • Taste preference: Great Danes have preferences for certain flavors and textures of food, and if their new diet is not appealing to them, they may refuse to eat it.
  • Digestive issues: Switching to a new diet can cause digestive upset, such as diarrhea or constipation, which can cause a Great Dane to feel sick and not want to eat.
  • Food allergies or intolerance: Some Great Danes may have allergies or intolerances to certain ingredients in their new food, which can cause gastrointestinal upset and loss of appetite.

If you are planning to change your Great Dane’s diet, it is important to do so gradually over a period of several days to allow their digestive system to adjust. 


A stressed Great Dane also experiences diarrhea including not eating, which may appear at the same time. 

Stress can cause a Great Dane to lose its appetite in different ways. One way that stress can affect a Great Dane‘s digestive system is by causing nausea, stomach discomfort, and other digestive issues. 

This can lead to a loss of appetite as they associate food with discomfort or they may simply not feel hungry.

Stress can cause changes in the Great Dane’s hormone levels, particularly the stress hormone. Elevated levels of the stress hormone can cause a decrease in appetite. 

Chronic stress can also suppress the immune system, leading to other health problems that can further affect their appetite. In addition to this, stress can lead to depression or anxiety, which can also cause a loss of appetite in Great Danes.

Stress and anxiety also cause a variety of symptoms including pacing, licking, drooling, yawning, crying, barking, and hiding.

Stress can come from a variety of sources such as a change in their environment or routine, new people or pets, loud noises, and other fear-related stressful situations.

Toxin ingestion

Poisoning in Great Danes can lead to a range of symptoms, including diarrhea and not eating. This is because many poisons can cause gastrointestinal upset and also affect a Great Dane’s appetite.

Loss of appetite can happen because of:

Nausea and/or vomiting: Many poisons can cause nausea or vomiting. When a dog feels sick, they may refuse to eat or drink.

Mouth ulcers and irritation: Certain toxins can cause ulcers or irritation in a Great Dane’s mouth. This can make it painful for the dog to eat or drink.

Organ damage: Some toxins may cause damage to a Great Dane’s liver, kidneys, or other organs which can lead to a loss of appetite, as well as other symptoms.

Neurological problems: Some poisons can cause neurological symptoms such as seizures or tremors which can make it difficult for a Great Dane to eat.

A Great Dane may accidentally ingest toxic substances such as household cleaners, contaminated food or water, pesticides, insecticides, poisonous plants, or human medications, which can cause diarrhea, loss of appetite, and other symptoms.

See Also: Great Dane shaking (Explained)

Side effects of medication 

Medications can sometimes cause side effects in Great Danes, including diarrhea and refusal to eat. 

Many medications can cause gastrointestinal upset, including nausea, vomiting, and diarrhea, which can lead to a decreased appetite. 

The taste or smell of the medication can also be unpleasant, making a Great Dane reluctant to eat.

Some medications also affect a Great Dane’s sense of taste or smell, altering the way food tastes or smells, which can reduce their desire to eat. 

A Great Dane’s mood and behavior can also be affected by some medications which lead to a decrease in appetite as a result of anxiety or depression.

Great Dane diarrhea and not eating: What to do

If your Great Dane  is experiencing both diarrhea and not eating, it is important to seek veterinary care as soon as possible. 

Here are  other signs that indicate that you should see a veterinarian immediately:

Severe or bloody diarrhea: If your Great Dane’s diarrhea is severe or if there is blood or mucus in the stool, this could be a sign of a serious underlying condition and requires immediate veterinary attention.

Other symptoms: Other symptoms may accompany diarrhea and not eating, such as vomiting. If your Great Dane is vomiting along with diarrhea, this can lead to dehydration and other complications. This requires immediate medical attention. 

Other symptoms to look out for include lethargy, breathing difficulties, signs of pain or discomfort, fever, and signs of dehydration, such as a dry nose or mouth and sunken eyes.

Suspicion poisoning: If you suspect that your Great Dane  has been poisoned, it is important to seek veterinary care immediately.

If your Great Dane  is a puppy or an older dog: Puppies and older are generally more vulnerable than healthy adult Great Danes so delaying treatment could result in their condition worsening or becoming more difficult to treat. Therefore, it is essential to seek immediate medical care.

Key Takeaway: Great Dane diarrhea and not eating

Diarrhea and not eating in Great Danes can be caused by a variety of factors. While occasional diarrhea is normal in Great Danes, persistent diarrhea alongside other symptoms such as not eating requires veterinary attention.

If you notice your Great Dane showing these symptoms suddenly or for extended periods of time, consult with your veterinarian to determine the underlying cause and appropriate treatment. 

By addressing the underlying cause of the symptoms and providing appropriate care, you can help ensure that your Great Dane remains healthy.

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