Can Dogs Eat Onions and Leeks?

As Shrek pointed out, onions have layers. However, whether leeks and onions are bad for dogs is a pretty easy question to answer and doesn't require any peeling. 

The answer is yes. These vegetables are terrible. I don't recommend giving your dog any member of the allium family - they are all, including onions, poisonous to dogs. 


  • Abdominal discomfort
  • Ataxia (wobbly gait)
  • Collapse
  • Diarrhoea
  • Drooling
  • Elevated heart rate
  • Exercise intolerance
  • Foul breath
  • Gastroenteritis
  • Increased respiratory rate
  • Inflammation of the digestive tract
  • Irritation of the mouth
  • Lethargy
  • Nausea
  • Pale gums
  • Panting
  • Reddish discolouration of urine
  • Vomiting
  • Weakness
can dogs eat onions and leeks

Onions especially contain a toxic principle called N-propyl Disulphide. It's a compound which breaks down red blood cells and causes anaemia in dogs. 

In small amounts, you don't need to worry too much if your dog eats onions, leeks or shallots. They might lose some red blood cells, but they probably won't become seriously ill. 

Moderate amounts will cause worse symptoms. Expect lethargy and weakness, but don't be surprised if there are very few signs. Whilst it's toxic to dogs, eating a small amount won't make your dog sick.

But what's a large amount? Well, dogs can get sick from eating 0.5% of their body weight in onions. Therefore, for a 50lb dog, it would only take one reasonably sized onion for them to start showing clinical signs of onion toxicity.

Any form of these allium plants can be toxic - dried, powdered, liquid, cooked or raw. They are all poisonous. Even in supplements, so be careful where you leave anything containing these ingredients. I recommend keeping items like onion powder out of reach from your dog to avoid onion poisoning. 

Top Tips:
  • Fence off gardens containing onions or leeks
  • Safely dispose of any unused allium vegetables when cooking
  • Never give your dog food that is seasoned with these plants
  • Keep all spices or supplements out of reach of your dog
can dogs eat leeks

Treatment Plan

If you feed your dog onions or leeks, you will cause all sorts of problems for your dog's digestive system. It will be painful, but usually, not fatal.  

The most dangerous part of allium toxicity is the fact that it targets red blood cells. In extreme cases, it can cause anaemia, or worse, death.

If you're concerned that your pet has eaten some of these vegetables, speak to your vet. It's always better to be overly cautious.