Why is my pet vomiting?

December 5, 2024
Caring for your pet

By Dr Duncan Houston, Veterinarian and Pet Nutritionist

At some stage your cat or dog will vomit… you’d be lucky if they never vomited in their lifetime. Hearing that abdominal heaving and churning followed by a splurge, hopefully outside, always sends chills down your spine… Why is my dog or cat vomiting?  Is it time to see the vet? 

There are so many things that cause vomiting, the same as with humans. Some can be for minor reasons whereas others can be more severe… so when can we know it’s time to see the vet? The answer for this is pretty much any time it occurs, but I’ll give you some information which may help you determine how severe it may be and whether you can monitor or should seek medical advice as soon as possible.

Regurgitation vs Vomiting

The first thing that should be deciphered is whether your pet is vomiting or regurgitating as the treatment for these is very different.

‘Regurgitating’ is when your dog brings up the contents from their oesophagus or stomach without the whole drama of abdominal heaving and churning. It’s more when food just slips back out without any warning. If this happens several times or includes blood in the contents then veterinary assessment is needed as soon as possible as worrying concerns include diseases of the oesophagus and oesophageal sphincter, which is the entrance to the stomach.

Whereas ‘vomiting’ is where the contents of the stomach and upper intestines are brought up forcibly, through muscle contractions. Most of the time it’s just digested food, maybe some grass if they ate some beforehand, but can also include some yellow bile. If the vomit includes blood, is dark, smells extremely bad like a metallic smell, green in colour, includes a lot of mucous, and has worms in it then it’s time to see a vet. Unless your dog has eaten a toxin, it’s not too much of a worry if they eat their vomit, but if they have eaten a toxin then stop them.

Signs Your Pet Feels Sick

Signs of nausea prior to vomiting may include hyper salivation (excessive drooling), behavioural changes such as depression/lethargy, licking lips and swallowing.

Reasons for Vomiting

There are A LOT of reasons for your pet to be vomiting and the best thing to do is find out WHY? These may include:

  • Dietary Changes
  • Food Intolerances/Allergies
  • Gastric Dilation Volvulus (GDV)... a twisted stomach common in large, deep chested dogs
  • Bloated stomachs
  • Foreign objects causing obstructions (string, rope, toys, cooked bones, etc)
  • Infections (Parasitic, Viral, Bacterial) anywhere is the body
  • Toxins (Commonly cleaning products and plants)
  • Heatstroke
  • Kidney disease (Acute or chronic)
  • Liver disease (Acute or chronic)
  • Pancreatitis
  • Medication reactions
  • Constipation
  • Cancer
  • Parvovirus / Panleukopaenia Virus
  • Colitis
  • Pain
  • Addison’s disease
  • Brain tumours
  • Diabetes
  • Eating too fast
  • Eating a lot of grass
  • Eating faecal matter
  • Exercising after eating
  • Inflammation of the stomach and/or intestines
  • Diarrhoea (Inflammatory bowel disease / Acute Haemorrhagic Enteritis or Haemorrhagic Gastroenteritis
  • Meningitis
  • Vestibular disease

If they only vomit once then generally it’s not too much to worry about but if they continue to vomit they can become dehydrated, painful in their abdomens, weak, depressed, lose weight, and younger animals can drop their blood glucose and place them at risk of seizures… time to see the vet.

What will the vet do to assess it?

The vet will initially do a physical exam assessing abdominal pain, temperature, dehydration as well as a range of other quick tests. Then if it is potentially more sister they may suggest to have xrays, ultrasounds, and blood tests performed initially. Tests that may take more time but be more comprehensive or fix specific issues may be faecal tests, such as faecal floats and Polymerase Chain Reaction (PCR) tests, endoscopies and biopsies. You should be more concerned with vomiting in younger and older animals as they are more fragile and vomiting can knock them around a bit.

What will the vet do to treat it?

For just basic vomiting where no specific issues are noted the vet will likely give your pet an injection of maropitant, an anti-nausea medication injection to stop the vomiting, and put your pet on a bland diet for a few days then begin to reintroduce them back into their original diet.

If the issue may be due to a dietary intolerance or allergy then they will suggest placing your pet on a single protein dietary restriction trial where you can only feed them one specific protein source for 8-12 weeks, such as a novel protein like goat. Your animal will NOT be able to have any other protein source during this time… so no chicken treats etc, they can have goat treats though but again they must not contain any other protein source like a mixed protein treat that may contain goat and chicken for example.

If it’s an infection then they’ll likely also place your pet onto antibiotics depending on what type of infection.

To sum up 

When they vomit, always think about the easy things it could be. Have they eaten something different today? Does this happen often? What’s the colour? What’s in the vomit? How many times have they vomited today? Are they acting normally or has their behaviour changed?

If you’re at all concerned, contact a vet and they’ll be able to help.

Vomiting is common, but it can mean something more sinister is happening inside.

Click to download Vomiting Guide PDF

About the Author - Dr Duncan Houston, Veterinarian and Pet Nutritionist

Duncan is a Veterinarian and pet nutrition expert based in Sydney who works mainly as a mobile vet, but also in emergency and general practice. He has a passion for aquatics and nutrition, working with several natural pet food companies for over a decade.

Triathlon and cycling were integral parts of Duncan’s life where he competed in several different countries taking home numerous achievements. He has always been active and maintains a healthy and exercise induced lifestyle, which he projects onto the animals he treats.

Duncan hopes he can provide you with up to date research and make it relevant to your pets at home. Better to be healthy now and get things right, such as nutrition early, as prevention is always better than cure.

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