Gastroenteritis in dogs and cats

By definition, gastroenteritis is an inflammation of the stomach (gastritis) and/or intestines (enteritis). Therefore, the associated symptoms are digestive: vomiting, diarrhea are almost systematic. Nausea associated with loss of appetite and abdominal pain are also possible. Gastroenteritis can appear acutely (in a few hours or days) or be more chronic.

There are similar causes between dogs and cats and different causes of gastroenteritis. Here are the most common.

Digestive parasites

Many internal parasites can cause diarrhea or vomiting, especially if the dog or cat is young. They are mostly worms (Ascaris,…) but also some protozoa such as coccidia. It is sometimes possible to find worms in the rejected gastric contents or in the feces. If the infestation by digestive worms is often not very serious, for kittens and puppies the problem can be more important especially due to dehydration caused by vomiting and diarrhea.

To avoid these inconveniences, it is necessary to deworm your animals regularly. The most effective is to do it once a month until the age of 6 months and then once every 3 months, at each change of season.


Unfortunately, our pets are often very curious and sometimes have a tendency to ingest toxins. Dogs are more often affected by intoxication than cats, the latter being more distrustful.

Poisoning can lead to gastroenteritis when your pet swallows an irritating product or substance. For example, a household product, bleach (cats love it), a toxic plant,…

Poisoning can also occur by ingestion of human medication.

If you have seen your pet eating a toxic substance, call your veterinarian quickly, who will advise you as soon as possible. Do not try to make your animal vomit because if he has ingested an irritating substance that has already irritated his digestive system once (oesophagus, stomach), vomiting will irritate these organs a second time and will therefore have an aggravating effect. Hospitalization may be necessary depending on the quantity and type of the product ingested because some of them cause other problems than digestive problems (convulsions, tremors, fever…).

It is also necessary to pay attention to spoiled or rotten food that your pet could eat (carrion found in the garden, garbage can robbed…) or to food surpluses (dog stealing 1 kg of salmon that you have prepared for example). In this case, the bacterial flora of the digestive system may be disturbed and may lead to gastroenteritis with diarrhea/vomiting. A symptomatic treatment will most often be put in place by your veterinarian to stop the symptoms but this will depend on the condition of your pet upon arrival.

Foreign bodies

A foreign body is any object that the animal swallows that is not part of its normal diet. For example, a bone is considered a foreign body because it can get stuck and block transit. When transit is blocked, symptoms appear: first vomiting because the foreign body irritates the stomach lining. Then if the foreign body manages to circulate into the intestine, the irritation causes diarrhea (which may contain blood).

For dogs, many foreign bodies are plastic toys that the dog swallows while playing. Depending on the dog’s behaviour, it may also unintentionally swallow pieces of wood or stones. Also be careful with your clothing, especially socks and underwear, which are often swallowed with some dogs.

For cats, it is most often linear foreign corns: it is a string or rope that the cat swallows while playing and that can get stuck. Sometimes a swallowed thread can be observed that is stuck under the cat’s tongue: DO NOT PULL on this thread because if it has already reached far into the digestive tract, by pulling it you risk tearing the digestive organs and causing serious injuries.

When you have caught your pet (dog or cat) swallowing a foreign object, don’t wait before taking it to your veterinarian. The quicker you do this, the less likely it is that the swallowed object will go into the digestive system and the easier it is to remove. The veterinarian will perform an x-ray or ultrasound to locate the foreign body and visualize its size. Depending on the case, the veterinarian may either induce vomiting or decide to operate (opening the stomach or intestines depending on the location).

One cause of gastroenteritis specific to young dogs: parvovirosis.

It is a viral disease (canine parvovirus type 2) extremely contagious and whose virus can resist for a very long time in the outside environment (several months in the stools), and which affects mainly unvaccinated puppies.

This virus multiplies in the digestive tract and causes damage there. The onset of symptoms is abrupt and often spectacular with severe vomiting and diarrhea with blood. The puppy is also feverish, is very tired and refuses to eat. It is a very serious illness that can kill within a few days, especially because of dehydration and fever. Don’t wait to see a veterinarian if your puppy has vomiting and diarrhea.

Fortunately, there is a vaccine against the parvovirus in dogs. It is necessary to vaccinate your dog very early because this disease affects puppies from the age of 6 weeks. Puppies living in groups are more vulnerable because of the contagiousness of the disease.

Warning: there are many other causes of vomiting / diarrhea.

Many diseases can be associated with symptoms of gastroenteritis and be different from the causes seen above. For example, liver problems, kidney failure, stomach/intestinal twists, digestive tumors and other metabolic disorders may cause these symptoms. Congenital malformations of the esophagus can also cause vomiting, etc…

Therefore, you should be careful what to do for your pet who shows signs of gastroenteritis. If it is a young dog or cat or an old dog or cat, it is more prudent to consult your veterinarian because these categories are more fragile.

Most gastroenteritis can be treated quickly with symptomatic treatment by your veterinarian (medication against vomiting and diarrhea), but care must be taken to avoid dehydration of the animal. It is essential to monitor the health of your dog or cat. If no rapid improvement is visible (less than 24 hours), if his condition worsens and other symptoms appear (blood, severe fatigue, severe pain, fever, …), it is important to return to your veterinarian quickly to perform further tests if necessary, or even hospitalize the animal.