Why Is My Pet Vomiting or Having Diarrhea?
Diarrhea accidents can be a bummer to clean up, but they can also indicate a medical issue that needs to be addressed. The treatment depends on the cause…and there are a lot of potential causes!
Understanding the Causes – and Why a Vet Visit Matters
At Two Rivers Vet Hospital, one of the most common concerns we hear from pet owners is:
“My dog has diarrhea but seems fine.”
“My cat keeps throwing up – what should I do?”
It’s understandable to wonder if your pet just has a mild upset stomach or if something more serious is going on. The truth is, vomiting and diarrhea are symptoms, not diagnoses — and the list of possible causes is long. That’s why a veterinary visit is often the fastest, safest way to get your pet feeling better.
Let’s explore some of the most common differentials (possible causes) behind these symptoms.
1. Dietary Indiscretion (“Garbage Gut”)
Dogs and cats love to investigate — and sometimes eat — things they shouldn’t. Table scraps, spoiled food, or trash can easily upset the digestive system, leading to vomiting or diarrhea. Most cases are mild, but some can lead to dehydration or pancreatitis.
2. Parasites
Worms like roundworms, hookworms, or giardia are especially common in puppies, kittens, and outdoor pets. Parasites can cause chronic diarrhea, weight loss, and vomiting — and are often contagious to other pets (and sometimes people!).
💡Fecal tests are the best way to rule this out.
3. Diet Changes or Food Sensitivities
Switching foods too quickly or feeding new treats can cause an upset stomach. Some pets may also develop sensitivities to ingredients like chicken, beef, or dairy over time (despite what some people think, it’s rarely grain-related). These pets may have intermittent vomiting, loose stools, or even skin issues.
4. Infections (Viral or Bacterial)
Viral infections like parvovirus (in puppies) or panleukopenia (in kittens) can be life-threatening if not treated quickly. Bacterial infections like salmonella or clostridium are also possible. These can affect even healthy adult pets and sometimes require specific medications to treat.
5. Pancreatitis
This painful inflammation of the pancreas is most common in dogs who have eaten rich, fatty foods (like bacon, butter, or holiday scraps). It causes vomiting, abdominal pain, lethargy, and sometimes diarrhea. It can become very serious without medical treatment.
6. Liver or Kidney Disease
When vital organs aren’t functioning well, toxins can build up in the bloodstream, making pets feel nauseous or lose their appetite. Vomiting, diarrhea, weight loss, and behavior changes may follow.
7. Foreign Bodies (Something Stuck Inside!)
If your pet eats a toy, sock, hair tie, or bone fragment, it may get stuck in the stomach or intestines — leading to repeated vomiting and a dangerous blockage. This is an emergency and often requires surgery.
8. Stress or Anxiety
Just like people, pets can experience stress-induced tummy troubles. Moving, new family members, or boarding can lead to temporary gastrointestinal upset. However, it’s still important to rule out medical causes before assuming stress is to blame.
9. Cancer or Chronic Disease
In older pets, vomiting or diarrhea that doesn’t respond to standard treatment may indicate a more serious underlying condition, like inflammatory bowel disease or cancer. Early diagnosis gives you the best chance at managing these long-term conditions.
Why It’s Important to See the Vet
Because vomiting and diarrhea can be caused by so many different things — some mild, some serious — getting a proper diagnosis is key.
At Two Rivers Vet Hospital, we may recommend:
A physical exam
Fecal parasite testing
Blood work or x-rays
Diet changes or prescription food
Medication to protect the GI tract or treat infection
🔬 The right treatment depends on the right diagnosis — and guessing at home can lead to delayed healing or worsening illness.
Call Us If You’re Concerned
Whether your dog vomited once or your cat has had diarrhea for several days, we’re here to help you figure out what’s going on — and how to get them feeling better fast.
