Can Dogs Eat Onions? No—And Here’s What To Do If Your Dog Does

Certain compounds found in onions can cause toxicity or poisoning in dogs.

When consumed, these toxic compounds are absorbed into the bloodstream and cause your dog’s red blood cells to break down—a process known as hemolysis—which can result in a condition called hemolytic anemia.

Hemolytic anemia occurs when red blood cells are destroyed faster than your dog’s body can produce new ones, resulting in a low red blood cell count. Red blood cells are essential because they carry oxygen in the bloodstream. When this process is compromised, your dog may show symptoms such as weakness, lethargy, an elevated heart rate, or even collapse.

All onions are toxic for dogs, as are garlic and garlic powder, leeks, shallots, chives and scallions/green onions all of which are part of the onion/allium family.

And it doesn’t matter what form they’re in. Raw onions, cooked onions, dehydrated onions and powdered onions are all harmful and potentially toxic for our furry loved ones. Yep, even onion rings!

Will a small amount of onions hurt your dog? Would even just a piece of onion be a toxic amount? Well, it depends on the size of your dog and how much onion is consumed.

“If a German Shepherd eats one small bite of a dish that contains onion, they might be fine,” says Dr. Wooten. “But a Chihuahua would not be.”

Generally speaking, though, most pets who eat more than 0.5% of their body weight in onions end up with toxicity symptoms.

Here’s what that means for your dog, according to size:

Again, it depends on your dog’s weight/size and how much is consumed, but symptoms of onion toxicity or poisoning can show immediately or take a couple of days to manifest.

Symptoms of onion toxicity or poisoning in dogs include:

• Vomiting
• Diarrhea
• Weakness or fatigue
• Pale gums
• Loss of appetite
• Jaundice (yellowing of skin or eyes)
• Red or brown urine
• Racing heart
• Panting

And in severe cases, the ingestion of onions in any form can be fatal for dogs.

If a dog consumes any amount of onion, pet parents should immediately seek veterinary care or call the Pet Poison Helpline at 800-213-6680.

When it comes to treatment, your vet may choose a variety of protocols, from inducing vomiting (if onions were eaten within one to two hours prior to the visit) to suggesting IV fluids or, in severe cases, blood transfusions.

They may also administer activated charcoal to help bind any remaining toxins in your dog’s digestive tract.

Your vet will likely continue to monitor your dog’s vitals—or suggest you do it from home—and may recommend hospitalization if further intensive care is needed.

To prevent your dog from nibbling on onion, follow these tips:

• Keep onions stored away: Store onions in a secure, airtight container and far out of reach from your pup. High shelves, cabinets or the fridge or freezer are safe options.
• Have rules in the kitchen: Consider establishing pet-friendly kitchen rules that prevent your dog from hanging out in the kitchen when you’re cooking meals or preparing food.
• Clean up messes immediately: If you spill onions on the kitchen floor, be sure to clean it up promptly. And avoid sharing human food that may contain onions in any form with your dog—no matter how hard they may beg you to lick the plate clean.