Vomiting and diarrhoea in cats and dogs: what to do and when to see a vet

18 August 2022 - 5 min read
A dog that has vomited

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

Pet insurance claims statistics show just how common it is. ManyPets had over 16,000 claims for diarrhoea and vomiting in 2021!

Vomiting was actually the most common type of pet insurance claim we saw in cats and diarrhoea was the third most common. Vomiting was the second most common claim we saw in dogs, while diarrhoea was the fourth most common.

The good news is, 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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What causes vomiting and diarrhoea 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 diarrhoea 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 diarrhoea and vomiting in pets that come to mind:

Gastrointestinal origin:

  • Parasites

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

  • Allergies

  • Infectious causes (bacteria/viruses)

  • Foreign bodies/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 issue (like vertigo in people)

  • Side effect 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 diarrhoea are as a clinical sign 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 diarrhoea looks like is not everyone’s favourite topic of conversation, but your vet is usually keen for 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 colours 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 colour 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.

  • Diarrhoea with blood – Dark black/tarry stools are definitely a concern when it comes to diarrhoea as this usually means there is blood being digested/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.

Should I feed my pet after vomiting and diarrhoea?

I usually say if your pet vomits or has diarrhoea one time and is otherwise acting normally, that 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 then offering a small amount of their food or something bland is typically safe. For example, if your dog vomits one time 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 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 potato are easy on the gut and usually palatable for pets.

I don’t often recommend people use things like sweet potato, pumpkin or squash for fibre 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 diarrhoea cases because that’s just protein and starch with little fibre, so it usually goes in one end and out the other.

Feeding a combination of things like this is ok 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 for both dogs and cats. Veterinary diets like this one are balanced maintenance diets for pets, and potentially can be fed long term for those with a sensitive gut.

When should I see a vet about vomiting and diarrhoea?

While many episodes of vomiting and diarrhoea are non-complicated and will resolve quickly, there are absolutely 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 a bland meal may be enough to help them through.

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

  • More than one episode of vomiting or diarrhoea, 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 toxin by making your pet vomit and/or blocks further toxin absorption….the better!).

  • If you see blood in the vomit or diarrhoea.

  • If your pet is on chronic medication for any disease/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.

ManyPets customers have free unlimited access to vet video calls – if you’re worried you can call them first and they can advise on whether you should see a vet straight away or if it’s safe to wait.

Unlimited free video vet consultations 24/7.

How will my vet treat my pet for vomiting and diarrhoea?

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-diarrhoea medications, gastrointestinal friendly diets, or even subcutaneous fluids.

Most online pharmacies can affordably fulfill and quickly dispense anti-nausea and anti-diarrhoea 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, faecal samples, imaging of the abdomen (x-rays, ultrasound), and intravenous fluids/medications.

Because pets can become dehydrated very quickly with persistent vomiting or diarrhoea, keeping pets for treatment in the vet hospital or out of hours vet is fairly common.

That can mean that treatment cost for diarrhoea and vomiting can be much higher than you’d expect – in 2021 the average pet insurance claim for diarrhoea cost £260.31 while for vomiting it was £425.99!

The right pet 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.

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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.