Can dogs eat onions?

If your dog had his way, he’d be quite happy to eat anything and everything he finds on his adventures each day—including what’s on your plate! 

Fortunately, there are loads of foods that you and your best friend can enjoy together (though perhaps you can have different plates!). But a word of caution: there are also many foods that aren’t so good for dogs. Sure, he might seem happy to chow down on whatever you give him, but that doesn’t mean he should.

[Learn more about the human foods dogs can and can't eat]

Knowing what to feed your dog to keep him happy and healthy requires a bit of homework. The first thing to know is that there are foods well beyond processed dog treats and canned meals that harbor amazing benefits for your pooch. 

So, what about onions? Onions belong to the Allium family, which also includes garlic, chives, and leeks. These vegetables are known for their strong taste and pungent flavors. Onions have long been used as a seasoning around the world, and harbors a huge range of health benefits. It’s a proven anti-inflammatory, antifungal, antiparasitic, and antiviral agent. But can dogs eat onions?

Can dogs eat onions? What the experts say

According to the American Kennel Club (AKC), onions are a no-no for dogs. In fact, onions are toxic to dogs. This pertains to the whole onion: the flesh, juice, and leaves. Whether raw, cooked, fried, or powdered, onions are believed to be harmful for dogs. This includes products made with processed onion powders or any members of the allium family (garlic, shallots, leeks, and chives). 

The risks of giving your dog onion

Vets say they also discourage feeding dogs raw onions. This is largely because of the negative effect onions can have on red blood cells. Onion and other members of the allium family contain a compound called thiosulfate. According to the Merck Veterinary Manual, thiosulfate is fine for humans but can be toxic for dogs. In fact, both onions and garlic in any form (this includes onion powder!) can lead to a life-threatening form of anemia in dogs if given in large amounts. This is because dogs cannot digest thiosulphate, so it builds up in the gut. This causes hemoglobin to clump together and can potentially lead to blood cells rupturing and anemia. Symptoms can include weakness or lethargy, vomiting, diarrhea, difficulty breathing, pale or bluish gums, and/or an increased heart rate. 

Of course, this is a worst-case scenario! Some dogs—especially small dogs—may be more susceptible to the toxic effects of onion than others, and react after eating very small amounts. 

However, even if your dog escapes the dreaded onion toxicity, he may not escape the gastrointestinal effects that onions can have. Whether raw, cooked, or processed, onions can wreak havoc on the gut and cause bloating, gas, cramps, and diarrhea. 

In short, onions aren’t really worth the risk.  

What to do if your dog eats onion

So, you think your dog ate onions? Don't panic—there’s a good chance that your dog didn't actually swallow a piece of onion that he finds, simply because he won’t like the taste. But then, some dogs are also prone to gobbling up their food rather quickly! So, if your dog has accidentally wolfed down an onion, keep a close eye on him for the next 24–48 hours. Onions can be toxic to dogs, so look out for symptoms of onion toxicity. This can include: 

• Unusual fatigue or lethargy
• Weakness
• Loss of appetite
• Pale gums
• Fainting
• Reddish urine
• Vomiting
• Elevated heart rate
• Panting 

If your dog shows any of these symptoms, the first thing you should do is take him to the vet. The vet will test for hemolytic anemia and figure out whether or not he’s suffering from onion toxicity. In most cases, toxicity will require veterinary attention. This may mean induced vomiting (depending on how recently the onions were eaten) or close monitoring until your dog's body can produce enough healthy red blood cells to replace the damaged ones. In extreme cases, your dog may require a blood transfusion.

With all this in mind, it’s probably a good idea to keep onions as far away from your pooch as possible. Store them in a box in your kitchen cupboard where your dog can’t get at them. If you like to use onions in your own meals, keep your dog out of the kitchen while you’re preparing them. It’s not uncommon for dogs to sample scraps that fall to the floor, and he won’t know how dangerous one thing is from another. 

Alternatives to serving your dog onion

So, onions are out—but lots of other vegetables are definitely in! They’re also highly recommended. Vegetables contain the fiber that dogs need to keep their digestive function in good shape. Insoluble fiber is particularly important because it helps to move waste along the intestines, keeping your doggo regular. Soluble fiber is also great because it nourishes his gut microbiome, which contributes to his overall immune health and wellbeing. 

To add crunch and flavor to your dog’s diet, try fresh carrots, green beans, or cucumbers. Broccoli, Brussels sprouts, and cabbage are also fine in small amounts. These vegetables are a great source of vitamins A, C, and potent antioxidants, just be sure to chop them up finely and feed minimal amounts in the beginning to allow your dog’s gut to adjust. Cruciferous vegetables such as cabbage can cause just as much gas and bloating in your dog as they do for you! 

And don’t forget about fruits! Fruit makes a great dog treat, and a much healthier alternative to sugar-laden treats you’ll often see in pet stores. Blueberries, raspberries, pineapple, oranges… all of these are just fine for dogs. Again, moderation is key. Some preparation is also required with fruits that contain stones, skins, or pits.

Learn more about foods dogs can and can't eat

• Can dogs eat onions?
• Can dogs eat plums?
• Can dogs eat strawberries?