Health Topics  >  Digestive  >  Eating Less

What causes dogs to have a decreased appetite?

Generally speaking, dogs are who are not eating or refusing to eat can be affected by one or more of the following:


Similar to people, dogs will not eat normally if they are feeling nauseous. The most common reason would be that they have eaten something that has upset their stomach. Consider whether your dog could have gotten into something:

  • Did the garbage look disturbed?
  • Did they grab something off the counter?
  • Did they pick up something while on a walk?
  • Did they drink from a communal bowl of water at the dog park?

The feeling of nausea may or may not be accompanied by vomiting. Other common symptoms include drooling and lip smacking. If your vet suspects your dog is nauseous, they will likely administer medication to reduce nausea and prevent vomiting.

Gastrointestinal Disease

The gastrointestinal tract, commonly called the GI tract, includes the esophagus, stomach, and small and large intestines. Inflammation, infection or ulceration within any of these sections of gastrointestinal tract could all cause a dog to eat less or stop eating altogether.

Vomiting, diarrhea, blood in the stool, or dark tarry stool often accompany GI disease. Your vet may assess your dog through a combination of physical palpation, bloodwork and imaging.

Any kind of stomach upset or gastrointestinal disturbances will usually cause a change in appetite. Look out for other symptoms like vomiting and diarrhea.

Dental Disease

Dental disease is very common in dogs. Because dental issues are often painful, dogs with a sore mouth may try to avoid chewing. This can result in them chewing more with one side of the mouth than the other, or only eating when given soft food and treats.

Infected teeth, tooth root abscesses, and broken teeth can become acutely painful, while gingivitis and infection below the gumline are more chronic and can contribute to a slow decline in appetite. Some dental concerns require dental x-rays to diagnose, while others are obvious just by looking in the mouth. Tooth extraction is commonly necessary in the case of infected and broken teeth.

Dietary Boredom

Most dogs do well being fed the same food daily. Unlike people who crave variety in their diet, most dogs are happy with the routine of their daily feeding and may even experience stomach upset if new foods are introduced.

However, it is possible that some dogs become bored of their diet and this may present as disinterest in their food, and not rushing over to their bowl like they used to. They may also take longer to finish their food. It is important to take note of the volume of food being consumed over time, not just in one visit to the bowl.

Boredom is usually a rule-out diagnostic, meaning testing may be required to make sure nothing more serious is causing the loss of appetite. If your pet is turning their nose up at their food, it is generally safe to try something different to see if you can pique their interest.

Dogs can get bored of eating the same food daily. If switching their diet, remember to do so gradually to avoid an upset stomach.


Changes in their environment can cause a pet to feel stressed. This could include things like:

  • Changes to their daily routine
  • Changes to their owner’s routine
  • A new home or environment
  • A new family member
  • Construction or other loud noises 

If the stressor cannot be removed, working with a behaviorist or anxiety medication and supplements may need to be considered. It is important to rule out illness related causes of loss of appetite before presuming it is stress related.

Pro Tip: Although decreased appetites can be caused by environmental factors such as dietary boredom or stress, these are typically ‘rule-out’ diagnostics only after other illness-related causes have been tested and ruled out.


The pancreas is an important organ for the digestion of food. Due to ingestion of a high fat meal, some medications, pancreatic trauma or, more rarely, tumors, the pancreas can become inflamed. This is usually very painful, and may be accompanied by vomiting, diarrhea, and low energy in some cases.

If your veterinarian suspects pancreatitis, they will likely recommend a special blood test and may also recommend ultrasound imaging. Hospitalization is typically required in more serious cases.

Kidney Disease

Kidney disease in dogs can occur suddenly, called acute kidney disease, or be a chronic condition which is slower in onset, called chronic kidney disease. If your dog abruptly stops eating, blood and urine testing will likely be done to assess organ function, including kidney parameters. 

Treatment will depend on the suspected cause, and whether your dog has acute or chronic kidney disease. Intravenous fluids are often required for rehydration in the short term, with special diets required in the long term. 

References for Decreased Appetite