How to deal with vomiting and diarrhea in cats and dogs

August 18, 2022 - 5 min read
This article is not intended to be a substitute for professional veterinary advice, diagnosis, or treatment. Always seek the advice of your veterinarian with any questions you may have regarding your pet’s care, treatment, or medical conditions.
A dog that has vomited
A dog that has vomited

Vomiting and diarrhea are by far and wide one of the most common issues we see in general and emergency vet practice.

Pet insurance claim statistics show just how common it is. Vomiting was actually the most common type of pet insurance claim we saw in cats, and diarrhea was the third most common. Vomiting was the second most common claim we saw in dogs, while diarrhea was the fourth most common.

The good news is that, in many cases, gastrointestinal (GI) upset can be resolved with supportive care and time. The less-good news, however, is that GI upset can also be a serious problem.

But how can pet parents know when to be worried? Let’s take a deeper dive into GI upset and how you can look after your pets.

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Causes of Vomiting and Diarrhea in Dogs and Cats

A common misconception pet parents have about GI upset is that it automatically means the primary issue is with the gut itself. Interestingly, the list of things that can cause vomiting and/or diarrhea is probably a mile long.

Almost any of our pet diseases can present with vomiting as the primary concern owners bring up at the vet.

Here’s a list of causes of diarrhea and vomiting in pets that come to mind:

Gastrointestinal Origin

  • Parasites

  • Dietary indiscretion (I ate something I shouldn't have)

  • Allergies

  • Infectious causes (bacteria or viruses)

  • Foreign bodies or gut obstructions

  • Toxins

  • Primary GI disease (food allergy or inflammatory bowel disease)

  • Pancreatitis

  • Abrupt changes in diet

Non-Gastrointestinal Causes

  • Kidney disease

  • Liver disease

  • Diabetes

  • Hyperthyroidism

  • Cancer

  • Addison’s disease (hypoadrenocorticism)

  • Vestibular issues (like vertigo in people)

  • Side effects of some medications

  • Stress or anxiety

I could go on, but I think this list helps give people an idea of how non-specific vomiting and diarrhea are as clinical signs in our pets.

It’s important for pet owners to keep this in mind when seeking veterinary care for tummy upset because any hints from the pet's history leading up to the event can help find the cause and treat the problem.

What Your Pet’s Vomit Can Tell You

We know talking about what your pet’s vomit or diarrhea looks like is not everyone’s favorite topic of conversation, but your vet is usually keen on a description or a picture.

It can really help us figure out what caused it as well as how serious the scenario might be.

Some pet vomit colors to look out for are:

  • Vomiting yellow fluid: pet parents often get concerned when they see bright yellow in their pets' vomit. This is a compound called bile, which will often come from the early part of the small intestines. Typically, you’ll see bile in your pet’s vomit if they are throwing up on an empty stomach. This yellow color isn’t necessarily a source of panic, but we’ll touch more on when to seek vet care later!

  • Vomiting blood: This definitely warrants a trip to your friendly neighbourhood vet. Blood in your pet’s vomit may indicate ulcers, toxins, perforations in the gut, or bleeding problems.

  • Diarrhea with blood: Dark, black, or tarry stools are definitely a concern when it comes to diarrhea, as this usually means there is blood being digested or bleeding happening higher up in the gut. Poo with bright red blood is usually coming from the colon (lower gut) and has a long list of causes, including stress!

  • Eating grass and vomiting: Some pets eat grass when they feel nauseous, but honestly, most of them just do it because they’re bored or they like it! My dog loves to eat grass, and sometimes I wonder if he was a cow in another life.

Whether to Feed Your Pet After Vomiting and Diarrhea

I usually say that if your pet vomits or has diarrhea once and is otherwise acting normally, you likely don’t need to starve them for extended periods of time. This is particularly true for young pets and small pets, as they have less of a reserve when it comes to energy.

For most healthy adults, giving them a few hours post-vomiting to let them settle and then offering a small amount of their food or something bland is typically safe. For example, if your dog vomits once and is otherwise happy and still interested in food, I would tell a client to give them a break for the afternoon, then offer a third to half of their normal food amount for dinner.

If they keep this down, you can slowly work back to full amounts over the next few days. I never recommend that water be withheld.

Repeated episodes of GI upset or your pet showing other clinical signs should warrant a trip to your vet for further investigation. Concerning changes at home would include them being lethargic, weak, not interested in food, disoriented, or even restless and agitated.

If you want to feed vomiting pets something bland and easily digestible, simple proteins such as boiled chicken breast or plain cooked mince with the fat drained off (like turkey) along with white rice or boiled sweet potatoes are easy on the gut and usually palatable for pets.

I don’t often recommend people use things like sweet potatoes, pumpkin, or squash for fiber supplementation because the amount you need to give to make an impact is fairly large; it's just not practical.

Similarly, I don’t often recommend chicken and rice for diarrhea cases because that’s just protein and starch with little fiber, so it usually goes in one end and out the other.

Feeding a combination of things like this is okay for short-term use only, as it’s more of a supportive measure and not a long-term balanced diet.

Using a veterinary gut support diet like Royal Canin Gastrointestinal is a safe bet if people want something easy and balanced. It comes in wet and dry versions for both dogs and cats. Veterinary diets like this one are balanced maintenance diets for pets and can potentially be fed long-term for those with sensitive guts.

When to See a Vet about Your Pet's Vomiting and Diarrhea

While many episodes of vomiting and diarrhea are non-complicated and will resolve quickly, there are certain cases where timely intervention is important.

Like previously mentioned, if your pet vomits or has soft stool once or maybe twice, but is otherwise acting happy, energetic, and interested in food, then monitoring them at home and feeding them a bland meal may be enough to help them through.

Some of the following symptoms, however, suggest your pet should be seen by a vet (and not after waiting several days):

  • More than one episode of vomiting or diarrhea, particularly in a short period of time

  • If you know or suspect toxin ingestion of any sort, the sooner you seek veterinary care, the better (the sooner your vet removes the toxin by making your pet vomit and/or blocks further toxin absorption, the better!)

  • If you see blood in the vomit or diarrhea,

  • If your pet is on chronic medication for any disease or disorder,

  • If your pet is showing other clinical signs (lethargy, weakness, decreased appetite or lack of appetite, disorientation),

  • If your pet shows symptoms on repeated days,

  • If your pain seems to be in pain

How Vets Treat Pets for Vomiting and Diarrhea

Your vet will recommend therapy depending on their overall picture of your pet (their history, a physical examination, etc.).

For happy, bouncy, and well-hydrated pets, the vet may suggest that monitoring or simple symptomatic therapy is warranted. This can include things like anti-nausea medications, probiotics, anti-diarrhea medications, gastrointestinal-friendly diets, or even subcutaneous fluids.

Most online pharmacies can affordably fulfill and quickly dispense anti-nausea and anti-diarrhea medication prescriptions.

For older pets or pets with other clinical changes, your vet will likely suggest further testing and more intensive therapies such as blood tests, fecal samples, imaging of the abdomen (x-rays, ultrasound), and intravenous fluids or medications.

Because pets can become dehydrated very quickly with persistent vomiting or diarrhea, keeping them for treatment at the vet hospital or an out-of-hours vet is fairly common.

The right cat or dog insurance policy will give you peace of mind that you’ll be able to get your pet the treatment they need when they need it, even if it’s out of hours or they need an overnight stay to get them hydrated, healthy, and recovered.

Veterinary surgeon Dr. Kirsten Ronngren joined ManyPets in 2022. Alongside her extensive experience as a vet in small animal and feline-only clinics, Kirsten is passionate about online content creation. Kirsten’s a regular on ManyPets’ social media and video content with her no-nonsense attitude to keeping our customers’ pets happy and well.