Common Reasons Why a Dog Won't Eat

Some dogs live to eat, other dogs less so. We use food rewards to train service dogs, and the act of giving a treat is a source of much pleasure to both dog and owner. So if your dog goes off his food and refuses to eat, it can be deeply worrying – especially if that dog is a Labrador whose stomach capacity usually knows no limit.

A Symptom not a Condition

Loss of appetite is only a symptom. When a dog stops eating (known as “anorexia”) this doesn’t indicate one particular condition, but merely hints that something isn’t right or the dog feels unwell.

That “something” might be the dog is depressed by the arrival of a new puppy, the food is off, or he’s refusing to eat as an attention seeking strategy. With regards to physical problems, the issue might be anything from feeling slightly nauseous after eating garbage to a potentially life-threatening toxaemia due to kidney failure. This doesn’t mean you should panic if your canine companion refuses his chow – but it does mean you should keep a watchful eye on him.

The most important message when it comes to appetite loss is to be vigilant: look for clues, and if the dog becomes unwell seek veterinary attention. By monitoring your pet and taking precautions such as checking for diarrhea, making sure he’s passing urine, and watching for sickness, you can give the veterinarian valuable clues as to where the problem lies.

Dos and Don’ts

Before we look at specific conditions, here are some general points to take on board about what to do and when to seek help if your dog doesn’t eat.

  1. Don’t make a fuss: Some dogs thrive on attention, and making a drama out of a skipped meal can “feed” into that attention-seeking strategy. Dogs that learn this may then use not eating as a powerful tool to manipulate their owner; so be a step ahead and don’t fall into the trap of rewarding his poor appetite.
  2. Don’t offer an alternative food: If the dog isn’t eating because he’s ill, you need to know about it. He’s not going to starve if he skips a couple of meals (longer than this he needs to see a vet anyway.) If you tempt him with goodies, he may force himself to eat, and delay you realizing there is a bigger problem than just a loss of appetite.
  3. Do make sure he’s drinking: Dogs can go for weeks without eating and not come to harm – not that I’m advising this. However, it’s essential the dog drinks regularly. Without taking fluid on board he’ll rapidly dehydrate, which has serious consequences. Not eating or drinking means you should call the vet right away.
  4. Do gauge his demeanor: Is he bright and bouncy, but just not bothered about food? Or does he seem unwell, not want to walk or stir from his bed? A dog that isn’t eating but is otherwise fine is not an immediate cause for concern, but a lethargic, anorexic dog needs checking by your vet.
  5. Do look for other symptoms: Be alert for other signs such as vomiting, diarrhea, heavy breathing, or difficulty passing urine, and seek help if you see them.

Not Eating: Dental Disease

Have you ever had toothache? Real, throbbing, too painful to sit still toothache? If you have you’ll appreciate how sore it is, and how eating was the last thing on your mind. But then here’s the rub, as well as toothache there are other conditions which make it too painful for a dog to eat.

Whilst a dog with toothache from a tooth root abscess might not feel like eating, a dog with sore gums wants to eat but it hurts to do so. These dogs show subtly different signs which indicate there is a problem.
These include:

  • Begging for food, then not eating it
  • Pawing at his mouth
  • Starting to eat then jumping away from the food bowl.

So if your dog isn’t eating his dinner, pay close attention to his behavior – it will give you useful clues.
If you suspect his mouth might be the problem, take a close look.

Study his face: Is it lopsided? Some root infections are associated with facial swelling, especially just below the eye. So if he’s not eating and his face is swollen, he may have an infected tooth.

Look at his teeth: Are they pearly white or coated in grey-brown tartar? Sometimes you can’t even see the teeth because they are encased in a hard mineral deposit called tartar. This can hide problems with the tooth itself, plus it pushes against the gum causing gum recession.

Look at his Gums: They should be a healthy pink color. Any angry red lines, or worse, bleeding from the gums, is a sign of gingivitis and often associated with infection.

The best cure for a sore mouth is to address the underlying cause and seek the advice of your veterinarian. Treatments are likely to include antibiotics to settle infection, followed by an anesthetic, dental descale, and extraction of damaged teeth.

Not Eating: Breathing Difficulties

OK, perhaps you weren’t expecting this one, but breathing difficulties are an important cause of appetite loss. If you think about it, a dog that’s short of breath doesn’t want to take time out from breathing to chew and swallow food.

This is a good example of anorexia providing a clue there’s a bigger problem. In the case of breathing difficulties it might be the dog has fluid around his lungs (a pleural effusion), fluid in the lungs (pulmonary edema, perhaps from heart disease), a chest infection, asthma, or bronchitis. Whatever the underlying cause, it’s imperative to seek urgent veterinary attention because whilst not eating isn’t dangerous, struggling to breath is.

To work out if this might be the case, watch your dog carefully and paying special attention to the movements of his chest and tummy, and his overall body language.

Is his Breathing Normal? Normal breathing is a soft in-out movement of the chest wall. Unless your dog is a squish-faced breed like a pug or bulldog, breathing is usually silent, and doesn’t involve the use of tummy muscles. A normal dog at rest takes 20 – 30 breaths a minute, equivalent one breath every 2 – 3 seconds.
If you’re not sure, here are some other things to check out.

Does he Lack “Get Up and Go”? Dogs with breathing difficulties concentrate hard on their breathing. This means walking across the room is a huge effort, and they’d really rather stay where they are. The dog that refuses to get out of bed bears a closer look.

Can you see his Tummy Move? If a dog is struggling to get air into his lungs, he may recruit his abdominal muscles to help. What you see are exaggerated expansion of the tummy that co-ordinate with the movements of his chest wall. This is called “abdominal breathing” and a sign of breathing difficulties.

Is he Breathing Too Quickly? Very rapid breathing is OK if he’s just caught a Frisbee, but not great news if he’s a coach potato. Rapid shallow breathing at rest is another clue to distress.

If you suspect your dog isn’t eating because of breathing difficulties, contact your vet right away. Dogs are good at hiding when they’re having problems so if you’re seeing signs the chances are the problem is already quite advanced.

Not Eating: Fever

Dogs with a fever often don’t eat. It might be their high temperature is the result of a bacterial or viral infection, or because of a health problem such as pancreatitis (inflammation of the pancreas) or pyometra (infection in the womb).

A feverish dog may also be thirsty, so watch out for tell-tale signs of drinking more than usual. It is always best to get a dog with a high temperature seen by your veterinarian. She will assess if antibiotics are necessary to help fight a bacterial infection, or indeed if other measures are required such as surgery to remove the pyometra or intravenous fluids and pain relief for pancreatitis.

Not Eating: Toxins

In this instance “toxins” refers to natural poisons that build up in the body as a result of organ damage.
A useful example is the dog with kidney disease. His tired kidneys struggle to excrete those toxins which are naturally waste products of digested food. In the same way that you don’t keep food scraps from an old meal in your kitchen, neither does the body want the waste products of digestion hanging around.

A damaged kidney cannot get rid of these natural toxins in the urine and blood levels remain high. The dog then drinks more as an alternative way of diluting the poisons in his blood. In addition, these toxins are often irritants, and inflame the lining of the stomach causing feelings of nausea and sickness. Taken to an extreme they may even cause gastric ulcers.

In the case of the pyometra (womb infection) it is bacterial toxins that circulate in the blood stream, make the bitch feel nauseous and put her off her food.

These types of condition tend to give subtle clues that something is wrong – typically increased thirst as the dog tries to dilute the toxins and wash them form his system, often accompanied by vomiting, and loss of appetite.

Once again subtle clues are valuable warning signs of a more significant problem, and should not be ignored.

Not Eating: DietaryIndiscretion, and Stomach Bugs

When we have a stomach bug we rarely feel like eating. This is nature’s way of telling us to rest the stomach whilst the immune system fights the infection. Of course many dogs are a lot less discriminating about what they eat than people. That titbit of old burger found in the gutter is as a gourmet meal to a Labrador!

The typical Labrador’s dietary indiscretion is a common cause of temporary appetite loss, perhaps followed by a quick purge, then back to normal again. As a general rule, this type of nausea is temporary, lasting 24 hours or so.

If the dog is a bit subdued but not losing fluids (such as with sickness or diarrhea) then it’s acceptable to starve him, leave access to fresh drinking water, and monitor him. But if he’s not better the following day, then it’s time for a trip to the vet.

As with other conditions, not eating is not immediately dangerous, it’s the implications you need to be alert to. For instance if the dog starts vomiting repeatedly or passing bloody diarrhea, then call your veterinarian right away.

Not Eating: Stomach Ulcers

Stomach ulcers can and do happen in the dog, but for subtly different reasons to in people. The most common causes are:

  • Drug related
  • Kidney disease
  • Helicobacter (a spiral-shaped bacterium)
  • Addison’s Disease (Hypoadrenocorticism)
  • Stomach cancer

Of these kidney disease (see above: Toxins) and drug-related ulcers are by far the commonest. The symptoms of a stomach ulcer can in part reflect the cause (so a dog with kidney disease will be thirsty, have a poor appetite, and rank breath) but generally speaking a dog with an ulcer may show the following:

  • Appetite loss
  • Vomiting – often with blood
  • Abdominal pain
  • Digested blood in the stool
  • Weight loss

Drug-related Ulceration

If your vet prescribed a medication that must be given with food, this means either the food helps the slow release of the drug or the drug has the potential to cause gastric ulceration. In the latter, the food acts as a buffer and stops the drug coming into direct contact with the stomach wall.

Drugs known to cause stomach ulcers are steroids (eg prednisolone) and nonsteroidal anti-inflammatories or NSAIDs (eg meloxicam or carprofen). The latter is commonly prescribed for arthritic dogs. When given on an empty stomach they breakdown the protective mucus inside the stomach to expose the delicate lining and cause patches to die off, leading to an ulcer.

If your veterinarian suspects a stomach ulcer she may confirm this by endoscopy, where afiber optic camera is passed down into the gut. Alternatively, she may decide to start treatment straight away and make a retrospective diagnosis when the dog gets better.

Treatment involves medication such as sucralfate (antepsin) which forms a bandage layer over the exposed stomach lining and mops up excess acid. Also, newer anti-acid medications such as omeprazole are extremely effective at making the stomach a less hostile environment which allows the ulcer to heal. Of course, if medication triggered the ulcer then the former should be stopped.

Not Eating: Specific Conditions

There are numerous conditions such as pancreatitis, hepatitis and hepatic lipidosis which are associated with a loss of appetite. Of these, the most common are pancreatitis and hepatitis.


One of the pancreas’ jobs is to produce digestive juices to digest fat. Normally these strong acids stay safely within the gut, well away from delicate tissue. However, with pancreatitis the pancreas leaks and starts to digest itself and the tissue around it.

Pancreatitis is an extremely painful condition and the acute heartburn-type sensation puts dogs off their food. This is one time when Mother Nature knows best because by not eating, the pancreas stops producing digestive juices, which gives the pancreas a chance to heal.

A dog with pancreatitis may recover through starving himself, but unfortunately this condition can also be aggressive and even life-threatening. Treatment ranges from simple starvation (resting the pancreas), to pain relief, through to intravenous fluids, anti-nausea drugs, and antibiotics.


“Hepatitis” simply means inflammation of the liver, and the term embraces several different types of liver inflammation. Some are the result of viral infections (Adeno Virus) and others are bacterial infection from the gut (cholangiohepatitis).

The symptoms are often vague, such as appetite loss, lack of energy, and the dog may become jaundiced and very ill very quickly. Seeking veterinary attention quickly is key to giving your dog the best chance of recovery. Hepatitis has the potential to be serious, but also many dogs (depending on the exact nature of the hepatitis) go on to make a good recovery.

And Finally

The take home message is if your dog stops eating, be alert for signs of ill health. If his appetite doesn’t pick up after 24 hours, or if other symptoms develop, contact your veterinarian. Treating a problem early can prevent complications and improve the chances of him making a full recovery.


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