Recurring vomiting in dogs and cats: when to investigate

The first useful distinction is between vomiting and regurgitation, because they point to different problems and steer toward different investigations. Vomiting is an active act: there is nausea, belly contractions, often drooling first, and the material brought up is usually already partly digested, sometimes with bile. Regurgitation is passive: food comes back up without effort, often right after the meal, still in a tube shape and undigested, without the contractions typical of nausea.

This difference matters because regurgitation points toward the oesophagus and vomiting toward the stomach and intestine or toward general causes. Describing to the vet which of the two you saw, and how it happened, guides the investigation far more than you might expect. A smartphone video of the episode, when you can film it, is worth more than any verbal description, because it clearly shows whether there was effort or not.

A single episode in an animal that stays lively, eats, drinks and behaves normally often has trivial and passing causes. Vomiting that keeps coming back over time, or that comes with other signs, is a different matter and deserves investigation. The table helps place the situation, but does not replace the vet's judgement.

The key is not a single number but the overall picture. A cat that occasionally vomits hairballs is different from a cat that vomits food twice a week for a month while losing weight: the first can fall within normal, the second does not. When in doubt, the frequency that keeps repeating is the real signal that something should be looked into.

Some situations do not allow waiting and must be handled as emergencies. Recognising them is the most important part, because delay can make the difference. If one of these signals appears, contact with the vet or an emergency facility should be sought at once.

• Blood in the vomit, bright red or like coffee grounds, or black tarry stools.
• Repeated attempts to vomit without bringing anything up, especially in a large dog with a swollen hard belly: possible gastric torsion, an absolute emergency.
• Continuous vomiting that will not stop, with the inability to keep down even water.
• Marked depression, pale gums, laboured breathing or clear abdominal pain.
• Suspected ingestion of a foreign body, a toxic plant or a dangerous substance.
• Vomiting in a puppy or kitten, which dehydrate very quickly, or in an animal with known conditions such as diabetes or kidney failure.

When vomiting is not an immediate emergency, the time before the visit is well spent gathering information. An orderly diary of the episodes turns a vague account into useful data and often shortens the path to a diagnosis. Here is how to proceed usefully.

1. 1

   Note the date, time and relationship to meals

   Record each episode with the time and how long after eating it happened. The link with the meal is one of the most informative clues.

2. 2

   Describe the content and appearance

   Digested or whole food, foam, yellow bile, grass, presence of blood or foreign material. If you can, photograph before cleaning up.

3. 3

   Record how the animal is for the rest of the day

   Appetite, thirst, energy, stools and behaviour. An animal that vomits but stays bright is different from one that is dull and off its food.

4. 4

   Check access to unusual foods and objects

   Leftovers, rubbish, plants, toys or objects that could have been swallowed. Recent food changes or new treats should be noted.

5. 5

   Track hydration and frequency

   Check that it drinks and keeps fluids down. Count the episodes: knowing whether it is two in a month or two a day changes everything for the vet.

6. 6

   Do not fast for long without guidance

   A short rest for the stomach can help in an isolated episode, but prolonged fasting is dangerous, especially in cats and puppies. When in doubt, ask the vet first.

The causes of recurring vomiting are many and cannot be diagnosed at home. It is still worth knowing the main categories, because they help you understand why the vet asks for certain tests. There are causes linked to the digestive tract, such as chronic inflammation, food intolerance, parasites or foreign bodies, and general causes that also show up with vomiting, such as kidney, liver, pancreatic or hormonal problems.

In the older cat, hyperthyroidism and chronic kidney disease are frequent causes to keep in mind, while in dogs and cats of any age a diet change that is too fast or access to unsuitable foods explain many episodes. Precisely because the possibilities are so many, the diagnostic path starts from the history and the visit and continues, when needed, with blood, urine and faecal tests and with imaging. The diary you kept is the starting point of this path.