A dog or cat that vomits from time to time is common, and usually nothing serious. But some vomiting should ring alarm bells. Here is how to tell the difference, when to worry and what to do.

Vomiting or regurgitation?

The distinction is useful: regurgitation brings food back up undigested, straight after the meal (usually a problem with the oesophagus). Vomiting expels food that is already digested, bile or fluid (a problem with the stomach, or something more general). In dogs and cats, the occasional vomit is unremarkable — they even eat grass at times to settle their stomach. Worth knowing: rodents, birds and reptiles cannot vomit, and a ferret shows nausea by grinding its teeth (always to be taken seriously).

Which signs should alert you?

  • Repeated vomiting, or vomiting that lasts more than 24 h
  • Blood in the vomit, a foul smell, bile in quantity
  • The animal cannot even keep water down, grows weak, hides away
  • A painful or swollen belly, excessive drooling
When to seek help quickly — See a vet without delay if the vomiting is repeated or contains blood, if your pet cannot keep water down, if its belly is hard or painful, if you suspect it has swallowed an object or a poison, or in a puppy or kitten. A cat that is vomiting and may have swallowed thread or string is an emergency.

Where does it come from?

The most frequent cause is simple gastritis (inflammation of the stomach). But there are plenty of others: a swallowed foreign body, a blockage, liver or pancreas disease, poisoning, or a more general illness. The vet narrows down the diagnosis from the signs, sometimes with a blood test, an X-ray or an ultrasound scan.

Mistakes to avoid

  • Forcing food or drink during the acute phase: better to rest the gut for a few hours, then offer small amounts of water.
  • Giving a human anti-nausea medicine: some are dangerous.
  • Shrugging off repeated vomiting ‘to see if it passes’, especially if your pet may have swallowed an object or some string.

Prevention

Keep small objects, string, toxic plants and foods out of reach; make any change of diet gradual; worm your pet regularly. Many avoidable vomits come down to something that was swallowed.

The key points: a single vomit in an otherwise well dog or cat is nothing to fear; but repeated vomiting, blood, or a listless animal that cannot keep water down means seeing a vet fast.