If you’ve owned dogs for any period of time, you’ll be well aware of their less pleasant habits… However, there are very few that are as disgusting to us as eating their own sick! That awful “retch… retch… heAVe… slurp slurp slurp” is something none of us enjoy hearing from behind the sofa, especially if the culprit then trots round to give us a friendly kiss! But why do they do it, and is it safe?
First, we need to distinguish between 2 separate conditions. While dogs do vomit, they also regurgitate, and these aren’t the same thing – nor do they have the same causes.
Vomiting is an active process, preceded by nausea (feeling sick, and typically looking unhappy and drooling) and retching. What comes up is stomach (and sometimes small intestine) contents, mixed with acid and, often, bile. Regurgitation, on the other hand, happens if the food never made it as far as the stomach – typically, what comes out is chewed food mixed with saliva and mucus.
Vomiting is a protective response – intended to protect the dog from poisoning. It is triggered by a special part of the brain called the CTZ (chemo-receptor trigger zone) that initiates vomiting if it detects over-fullness of the stomach or small intestine, or unusual chemicals in the bloodstream. By far the most common cause in dogs is what we call “dietary indiscretion”; in other words eating something nasty! Other causes include swallowing of toxins, certain medications, stomach ulcers, gut infections, kidney disease, liver problems, inflammation of the bowel, pancreatitis, and many, many more. Regular vomiting or repeated vomiting needs investigation, but because of their rather “unfussy” approach to what constitutes food, most dogs will occasionally vomit.
Regurgitation occurs when, for some reason, food is not pumped all the way down into the stomach and instead sits in the oesophagus (gullet). Common causes include oesophagitis (inflammation or irritation to the gullet lining), obstructions (from scar tissue, foreign bodies, or tumours), and functional disorders such as megaoesophagus (where the gullet becomes dilated and “floppy”). However, occasionally dogs will regurgitate after food for no obvious reason – this may be due to eating too fast, but the reasons aren’t fully understood. Nevertheless, if your dog is regurgitating regularly, they really need to be checked out by your vet.
Dogs may eat either vomited or regurgitated material – although it is more common for them to re-eat regurgitated material, fresh vomit is also sometimes consumed. There are a number of reasons for this.
They want to feed someone. It is normal for wolves and other wild canines to regurgitate food to feed puppies. In fact, one study found that 60% of domestic dogs are reported to do so when there are puppies in the household. It is possible that your dog is regurgitating in front of you because they love you and want to give you food… but when you don’t want it, they gobble it up again so it doesn’t got to waste!
To hide the evidence. Not from us, of course, but it is possible that dogs eat their vomit to conceal from other animals that they’re unwell. This is, for example, why dogs eat their placentas after giving birth, and the same instinct could be relevant here.
As usual in the veterinary world, “it depends”! If the dog has regurgitated normal food, then it isn’t harmful for them to eat it again (ultimately, it’s still food!). However, if they have vomited something up, then there’s a good chance that they’re just re-eating the toxin or bad food that made them sick in the first place. In addition, vomit contains a lot of acid which can damage the teeth – pitting the enamel surface and making dental disease more likely in the future.
As a result, I generally recommend trying to discourage it by removing the produced material as soon as possible!
A dog that vomits or regurgitates once isn’t really a concern – although I would recommend you try to stop them eating it again! However, regular regurgitation (i.e. more than once every few weeks at the very maximum) definitely needs to be seen by your vet, because there’s probably an underlying cause that needs investigating.
A dog that has vomited once or twice in a day normally won’t need seeing – offer plenty of water, withhold the next meal (to allow the stomach to empty fully), and then try to feed them a bland diet for 24 hours and then reintroduce normal food. If the vomiting persists despite this “first aid”, contact your vet. Signs that a dog may need to be seen more urgently include: