Can Dogs Eat Green Onions?

Dogs should not eat green onions. The Thiosulphate content in green onions (also known as scallions, spring onions) is harmful to dogs. Thiosulphates can cause hemolytic anemia in dogs, a condition that destroys their red blood cells.

Even small amounts of these allium family members can cause poisoning. Symptoms include weakness, lethargy, pale gums, rapid heart rate, panting, vomiting, diarrhea. If you suspect your dog has consumed green onions, take them to a vet immediately.

Last Updated on September 20, 2023

Green onions are an essential herb for all food lovers. It’s a popular ingredient in Asian and Latin-American cuisine that is often used for garnish. They can be eaten cooked or raw. And they make your simple home-cooked meal look like they came out of a magazine. Unluckily, you cannot share this joy with your dogs. Dogs cannot eat green onions. They are toxic to dogs and can be life-threatening. Read on to find out why they are dangerous and what you can do if your dog ate green onions.

dog close up in grass

What are green onions?

Green onions or scallions are part of the Allium family. They are closely related to chives, leeks, onions, and shallots which are all toxic to dogs. Although the most common species that cause toxicity in canines are onions, leeks, garlic, and chives – garlic being the most potent. They are five times more potent than onions.

Green onions contain a substance called n-propyl disulfide that can damage your dog’s red blood cells. They can build up over time and can be extremely dangerous for your pet. I will expand on this further in the next part.

All parts of the onion are toxic to dogs and all forms of onion are dangerous. Whether they are cooked or raw, they should be avoided at all costs. This applies to other species of the Allium genus as well. The American Kennel Club suggests that “it only takes 100 grams of onion (about the size of a medium onion) per 20 kilograms of a dog’s weight to cause toxic effects.” This means that a 50lb dog can get ill from a medium-sized onion.

Any dog can get sick from eating a good amount of onions. However, dog breeds of Japanese descent are more susceptible to onion toxicity like Akita, Japanese Chin, and Shiba Inu.

What they do to your dog

When your dog ingests onion, the substance they contain known as thiosulfate, cannot be digested since dogs don’t have the enzyme for it.  What’s more, is that N-propyl disulfide, also found in onions, attaches to your dog’s red blood cells and causes damage. It tricks your dog’s body to think that the red blood cells are a threat and attacks them. This dangerous process is called hemolysis.

When hemolysis is left untreated, your dog can develop hemolytic anemia, Heinz body anemia, or methemoglobinemia. All of which is an indication of damage to red blood cells. 

green onions with knife and food

My dog ate scallions, what now?

If you suspect that your dog ate a large amount of onions, call your vet immediately. If your dog is a small breed, a smaller amount of onion can already be potent to your dog. However, Hemolysis can be prevented especially when your dog ate onions just recently. Your vet may induce vomiting to remove undigested herbs from his gastrointestinal tract using activated charcoal. However, do not attempt to induce vomiting on your own. After this, your veterinarian will most likely recommend a diet low in oxidants for your dog and tell you to monitor any signs of anemia.

For extreme cases, your dog may need to stay in a veterinary hospital for a few days. Supplemental oxygen and blood transfusion may be performed until the bone marrow can generate new, healthy red blood cells. IV fluids and medication can also be done to alleviate GI symptoms.

Still, even if it was in small amounts, you need to call your vet. Symptoms don’t appear right away. An early diagnosis can help lessen the amount of toxin your dog may absorb.


Symptoms may occur as early as the day after your dog ate onions. Some cases also take several days before symptoms are seen. According to the ASPCA and AKC, the symptoms you must watch out for are:

  • Lethargy
  • Weakness
  • Fainting
  • Vomiting
  • Blood in urine
  • Elevated heart rate
  • Panting
  • Pale gums
  • Decrease in appetite
  • Exercise intolerance

Some of the symptoms can also be:

  • Foul breath
  • Hyper-salivation or drooling caused by mouth irritation
  • Abdominal pain
  • Diarrhea
  • Wobbly gait

If you observe any of these symptoms, call your vet immediately.


Prevention will go a long, long way when it comes to onion toxicity. Dogs normally don’t like the taste of these plants but if you have your own herb garden, fence off the part where green onions, garlic, chives, and leeks are planted. Dog fences are very effective in keeping your dog away from places you don’t want them to go. Make sure to dispose of the unused portions properly. Put away spoiled food with green onions in a sealed trash can or garbage disposal. And keep them out of reach from your dog.

Most importantly, do not give food scraps to your dog! I understand how this is the hardest part to do but green onions are present in a lot of food. Best to keep your dog away from the kitchen and your food.

dog walking with toy


Unbeknownst to our dogs, their digestive system differs from us. Whatever they see that we consume become instantly delicious in their eyes. If you leave onion rings on the table, even if they are dangerous for them to consume, they will happily gobble it! It is up to us to remember that some food can be toxic to them and green onions are one of them.

Dogs cannot eat green onion. If your food contains green onions, they are not for you to share. Onion toxicity is expensive to treat and is extremely dangerous for your dog’s health. If you cannot avoid giving human food, make sure they have no allium products. On another note, if you’re concerned about your dog eating the same dog food every day, other foods are safe for your dogs to eat.

If you found this helpful, make sure to share this information as well with other pet owners!


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