My Pet Won't Eat

Written by:

Ashley Gallagher, DVM
Published: May 04, 2016

Whether or not a pet eats is an essential indicator into how he is feeling.  There are countless medical and behavioral reasons that can affect a pet’s appetite.  It is important to not only know if he eats, but also how quickly or if he seems interested in eating but then walks away after smelling the food.  These are all clues that veterinarians can use to determine the underlying cause of why your pet’s appetite is decreased.

The most common reason that a dog or cat won’t eat is gastrointestinal upset.  Vomiting, diarrhea, lethargy, dehydration or fever will often accompany the clinical sign of decreased appetite.  In addition to using these symptoms as a guide, veterinarians also factor in age, medications, and known medical conditions to help guide them to what is causing the anorexia.

If a healthy young dog or cat comes into the hospital with a history of refusing food, lethargy and profuse vomiting, the most likely causes are foreign body ingestion, toxicity, a viral infection like parvo or a bacterial infection such as leptospirosis.  If that same young animal is having decreased appetite, diarrhea and fever, we want to make sure that intestinal parasites or overgrowth of bacteria in the intestines are not to blame. 

In addition to the above conditions, older dogs and cats develop other diseases such as hormone imbalances, organ failure or cancer that we need to consider.  Conditions such as diabetes, liver disease or kidney failure can make a pet feel extremely nauseous which results in refusal of food, often after smelling the food and seeming interested in eating.  The good news here is that many of these issues can be identified on routine blood work, which allows for a quick diagnosis and treatment plan.

Cancer can affect any cell in the body and presents in numerous ways, many of which are seen as decreased appetite. Cats very commonly develop lymphoma in the stomach and intestines.  With these patients, in addition to anorexia you can see any combination of weight loss, vomiting or diarrhea. The cancer does not necessarily need to be limited to the gastrointestinal tract to make a pet feel poorly which results in decreased appetite.

Stress is another culprit that results in a decreased appetite.  The anxiety can be from a temporary situation like a kennel stay away from home or it can be more permanent such as the case with many fearful and anxious dogs.  These poor critters get so worked up over everyday life, such as an owner leaving for work, that they will often not eat because of it.  Cats will often protest a change in diet by refusing to eat anything at all.  It is important whenever transiting a kitty to a new diet that you give them ample time to adjust to the idea by offering both the old and the new food for several days.  This allows them to feel they had a say in the diet change rather than an owner telling them what they must eat.

There are countless causes for why a dog or cat will develop a decreased appetite.  Often it is something simple that can be resolved with a few days of a bland diet and perhaps, if advised by your veterinarian, an over the counter medication to help settle the stomach.  It is important to monitor your pet closely and if the decreased appetite is not improving or additional clinical signs like lethargy, vomiting, diarrhea or fever occur you should contact your veterinarian.  Since our pets can’t speak to us it is critical that we listen carefully to the other ways in which they communicate.  Not wanting to eat is usually a clear sign that your pet isn’t feeling his best and may need medical attention.