So what's the deal with onions?

They’re such a common ingredient in our sauces, stir-fries and barbecues. But what actually happens when dogs or cats sneak something containing onion? Should you press the panic button?

Here’s the surprising low-down on onions…

They’re the topic of so many late night emergency calls that I’ve received over the years and are right up there with chocolate and grapes as one of the most feared foods. But is it all justified?

Well yes…and no. Like the onion itself…there are layers.

Onions CAN cause problems on two fronts. Straight onion is actually an irritant to the lining of the mouth and intestines and so can cause some excess salivation, vomiting and diarrhoea. But that won’t be deadly.

The most feared part comes from a chemical within onion (and garlic…they’re from the same family after all) that actually attacks your dog or cat’s red blood cells, causing them to burst. The more onion they eat, the more red blood cells they lose. And it’s this anaemia that’s behind the life threatening danger. It causes shortness of breath, fatigue, kidney damage and even death.

But before you need oxygen yourself, just hold up for a second. The crucial part is the amount of onion they need to eat BEFORE you see anything like these worrying signs. It’s surprisingly high.



For a 10kg Cavoodle, Poodle or Mini Schnauzer, it’s anything more than 150g. That’s about the equivalent of eating an entire onion. If they raided a barbecue tray of sweet cooked onion, it’s definitely possible though…

For a 40kg Labrador, it’s 600g or 4 average sized onions. While that’s beyond the level of just sneaking a sausage sandwich with some onions on the side, some bigger dogs may think it’s possible at a dinner party…

From my experience, it’s actually the repeated exposure to moderate levels of onion that is more likely to cause issues rather than just a small accidental taste.

So while the hype around a life threatening emergency isn’t justified from just consuming a small sliver, a bigger drama is still possible with a much bigger appetite and repeated access to onions. So it’s definitely worth keeping it off their radar…and responding if you think they’ve scored big…

Something to paw over...