how to decipher them.
If you own a dog, gastroenteritis is a term which you might run into often enough.
You bring your dog in to the veterinary clinic with diarrhea and vomiting. The chances that your vet will spring this word on you are pretty good. So what does it mean?
I don't know why—I blame my goofy bone—every time I come across this word I think of how a student who didn't do his homework would tackle explaining it: “Gastroenteritis is … when … something bad enters the digestive system.”
What grade do you think he'd deserve for that? Let's take a look.
Gastroenteritis refers to inflammation of the stomach and intestines.

The faithful suffix -itis stands for inflammation (e.g. arthritis, pancreatitis, gingivitis ...).
Gastroenteric refers to the stomach and intestines – gastrointestinal (GI). Sorry, nothing about actual entering.
However, the most common cause of gastroenteritis in dogs is dietary indiscretion, which actually is something inappropriate entering the system. Ha! It can also be caused by drugs, poisoning or infection.
Considering all that, I think our unprepared student deserves a C for his efforts.
Because of its many different possible causes and how it can vary greatly in its severity, gastroenteritis is actually quite a broad term.
Something makes the GI tract angry and it triggers a defensive mechanism – inflammation. Some of the many causes are
- dietary indiscretion
- abrupt change in diet (you've heard about gradual switching, haven't you?)
- poisoning
- infections
- food allergies
- autoimmune disease
You are most likely to face the acute form of gastroenteritis, but it can also have a chronic form.
The symptoms of vomiting, diarrhea, and loss of appetite may wax and wane, but they linger over weeks or months.
When do you worry?
The rule of thumb is violence of the symptoms and how long they last.
Violent diarrhea and vomiting, presence of blood, pain, fever, dehydration, lethargy, these are all signs that it's time to take action immediately. If the symptoms are relatively mild but chronic, you also want to pay attention and investigate the cause.
I was tempted to call for common sense, but is it still common sense when it's not so common?
I know people who run to the vet at a drop of a hat and I know people who shrug off quite violent lasting symptoms. Neither is a good idea, but when you're in doubt, err on the side of caution. It is better to rush to a vet with a simple garbage gut than to ignore a potentially life-threatening situation!
While acute symptoms are likely to get your attention, it is often easy to 'come to terms' with a chronic situation.
I know, I've been there. It is not that we didn't take Jasmine to vets. We did. But after countless fruitless visits we accepted the lack of diagnosis. That was a wrong thing to do and Jasmine paid for that. Chronic diarrhea is not normal! Where there is a symptom there is a cause.
Also beware of arbitrary symptom-based treatment. While there is a time and place for that approach, without a firm diagnosis it can do more harm than good.
Moderate diarrhea that lasts a day or two is likely nothing to be overly concerned about. I do worry when diarrhea is accompanied with vomiting though. Dr. Beatty's article gives a good of example why it is a good idea to take this seriously.
Our J.D. is a young healthy dog who'll eat about anything that fits in his mouth.
When he gets diarrhea, I have very clear suspicions. I put him on a 24 hour fast and all is well the next day. Sometimes he also does throw up. However, examining the vomit always makes it quite obvious why.
Jasmine is a different story. Even when her diarrhea isn't really bad, a 24 hour fast has never worked for her and medical treatment has always turned out necessary.
Know your dog and know your symptoms!
It's your dog's health!
Jana
Further reading:
Dog gastroenteritis
First Aid and Emergency Care: Diarrhea and Vomiting