Onions are a core ingredient in many recipes around the world. With about 105 billion pounds of onions sold globally each year, you’d be hard-pressed to find a kitchen without an onion or two sitting on the counter or in the fridge. But can dogs eat onions? If your dog gets into a bag of onions or eats a few scraps you drop while cooking, should you take them to the vet?
While onions are a staple in the kitchen for humans, they’re dangerous for dogs to eat. You should never feed your pup onions, or any food that contains onions or onion powder. If you cook with onions, it’s important to know the signs of onion poisoning in dogs and when you should take them to the vet.
Are Onions Bad for Dogs?
Yes, onions are bad for dogs. Even ingesting a small amount of onion can be harmful to canine health, so it’s important to make sure you keep them out of your dog’s reach.
Why Are Onions Toxic to Dogs?
Onions contain a chemical compound called N-propyl disulfide, which can damage red blood cells in dogs. Red blood cells are responsible for cycling oxygen between the lungs and the rest of the body.
Humans have enzymes that help break down N-propyl disulfide, protecting our red blood cells and making onions safe for us to eat. But dogs don’t have these enzymes. This means they aren’t able to fight off the compound before it causes damage.
What About Green Onions and Chives?
Dogs should never eat any type of onion, including green onions and chives. Like red, white, yellow, and sweet onions, green onions and chives are members of the Allium genus, which is toxic for canines. Avoid feeding your dog any food belonging to this genus, including leeks and garlic.
Symptoms of Onion Poisoning in Dogs
Immediate Effects
Some signs of onion poisoning may be apparent immediately or within a few minutes or hours of consumption.
Look for the following signs of onion poisoning, and take your dog to the vet if they exhibit any of the following symptoms:
- Vomiting
- Diarrhea
- Abdominal pain
- Loss of appetite
- Excessive drooling
- Lethargy or weakness
Delayed Symptoms
Some signs of onion poisoning may not show up right away. The N-propyl disulfide found in onions damages red blood cells in dogs. This can cause them to burst, leading to hemolytic anemia.
Hemolytic anemia may show up as soon as 24 hours after your dog eats onions. But it’s more likely to take a few days before you start seeing symptoms, which can include:
- Pale or yellow gums
- Increased heart rate
- Hyperventilation or difficulty breathing
- Weakness or collapse
- Dark red or brown urine
Long-Term Impact
Without treatment, onion poisoning can lead to serious health issues in dogs, including liver damage, collapse, or even death in severe cases.
How Much Onion is Toxic for Dogs?
According to a scientific review by Interdisciplinary Toxicology, toxicity broadly occurs in dogs who eat more than 0.5% of their body weight in onions. All forms of onion can be harmful, including raw, cooked, or dehydrated onions.
Since even small amounts can harm your dog, you should always try to keep onions away from your pet entirely.
What To Do If Your Dog Eats Onion
When To See a Vet
A dog who has eaten onions should be seen by a veterinarian as quickly as possible. If you suspect your dog has eaten more than a very small amount of onion, take them to the vet immediately. Don’t try to induce vomiting on your own unless you’re specifically instructed by a vet to do so.
If you’re not sure whether your dog has eaten onions or you need immediate advice, you can call your vet’s office or reach out to the following organizations for help deciding what to do:
- Pet Poison Helpline: (855) 764-7661
- ASPCA Animal Poison Control Center: (888) 426-4435
Treatments for Onion Poisoning
Treatment for onion poisoning depends on how recently the onion was ingested and the severity of the dog’s symptoms. In many cases, a vet will induce vomiting to expel the toxins from the dog’s body. They may also administer activated charcoal to prevent the stomach from absorbing toxins.
Once toxic material is removed, your vet will likely recommend monitoring and provide basic care to help your dog produce new, healthy red blood cells. In severe cases, your dog may also require supplemental oxygen and a blood transfusion.
Final Thoughts
Many human foods are safe for dogs to eat in moderation. Onions are not one of them. All onions are toxic to dogs, in addition to other members of the Allium genus, including:
- Red onions
- White onions
- Yellow onions
- Sweet onions
- Green onions
- Chives
- Leeks
- Garlic
Before you feed any human food to a dog, it’s worth checking with your veterinarian to make sure it’s safe for them to eat. By staying informed and taking precautions with your dog’s health and nutrition, you’re being a responsible pet owner and doing everything you can to ensure your pup has a long, healthy, and happy life.