02 December 2015

My Dog Ate Some Onion, Is This Dangerous? What should I do?

Onions are toxic to dogs if they eat them in a big enough quantity, they often get them in pizza and other human foods.  But what amount of onions would be toxic to a dog if swallowed? What symptoms would you expect? And how can an onion toxicity be treated in the dog? If in doubt you should take your dog to the vet at once.

My Dog Ate Some Onion, Is This Dangerous?
Onion can be toxic to dogs if they eat enough.
There are a number of potential toxins in the average house which are a danger to dogs and other pets which many owners are often unaware of, surprisingly one of these is onions. The problem is that dogs do not have the enzyme necessary to properly digest onion, where smaller amounts are involved then this can result in gastrointestinal symptoms such as vomiting or diarrhoea or indigestion. But where larger amounts of onions have been eaten then it can be much more serious dogs because the dog's red blood cells may then become fragile and break down. This can cause severe anaemia which can even result in death in some cases.

1. So how much onion is a toxic dose to a dog? : Thankfully it actually takes quite a lot of onions to be toxic to dogs in terms of anaemia. The rule of thumb which I personally apply is that a single meal of one pound of onions taken at one sitting can be dangerous to a 15 pound dog. { Which is quite a small dog } However be aware that smaller amounts of onion fed on a regular day in day out basis can still eventually cause anaemia. Actually in my experience problems related to onion toxicity in the dog are quite a rare event, the average dog is unlikely to eat whole raw onions and normally the amount ingested in pizza and other human foods is fairly minimal.

2. What symptoms would you expect to see where a dog has eaten a toxic dose of onion? : Initially these could include drooling, vomiting, diarrhoea and lethargy. If anaemia is going to occur the symptoms will appear some days later and then you might see pale gums and mucous membranes, blood in the urine, an elevated heart and respiratory rate and extreme exercise intolerance leading to collapse.

3. What treatment is available where a dog has eaten larger amounts of onions? :

A. As with a great many toxins if you can induce vomiting to recover the onions within the first hour after ingestion { Two hours at the very outside } then things should be OK. A commonly used way to induce vomiting in the dog is with 3% hydrogen peroxide { Not hair colouring peroxide } A usual oral dose is one teaspoon { 5 ml } per 10 pounds of body weight. Vomiting should occur within 15 to 20 minutes but if no vomiting occurs, you can safely repeat the process a second time.

B. On top of that activated charcoal given orally as soon as possible after ingestion can often mop up some of the toxins, doses of around 2 gram per pound of the dog's body weight given three times a day for a few days have been used.

C. If the amount of onion the dog ate was significantly less than the sort of toxic dose I mentioned above then the resulting gastrointestinal signs can be treated in a normal common sense way but you would still be wise to have your vet check your dog over just in case. A quick blood test will check for any more severe problems. As far as home treatment goes for an upset tummy you could consider giving the dog small frequent meals such as chicken, fish, scrambled egg etc. with a little rice, and if the dog picks up on this you can then gradually reintroduce his or her normal diet over the following days.

D. If you are suspicious that anywhere near a toxic dose of onion has been consumed by your dog then you have no course other than getting your dog to a vet as soon as you possibly can. Your vet may induce vomiting and give activated charcoal if you can get there quickly enough. But once clinical signs develop then supportive care such as IV fluids may be necessary and some dogs may require a blood transfusion.

I hope this article has been of interest to you.


Dr Scott