Can Cats Eat Onions?

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Onions are delicious added to any stew, soup or burger. They are a staple vegetable to have in the kitchen, which is why it's important to know if cats can eat onions. While onions may be a tasty food for humans, the same may not go for our feline friends.


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So can cats eat onions? The answer is no. Cats cannot eat onions.

Why can't cats eat onions?

Onions of any kind are dangerous for cats who are more sensitive to the toxic properties of onion than other species are, according to researchers at the Directory of Veterinary Products. Onions are a part of the Allium species of plants, which also includes garlic, chives, shallots, leeks, and scallions. Allium species contain a variety of organosulfoxides, which convert to sulfur-containing organic compounds when chewed. This is what gives onions a delicious, aromatic flavor to humans, but for cats — these compounds damage red blood cells, resulting in the cells not being able to carry oxygen to the brain.


Ingesting onions can also cause anemia (low red blood cell count), and, in severe cases, the anemia may lead to internal organ damage, organ failure, and even death, according to the ASPCA.

All onions, whether cooked or raw, are poisonous to your cat.

How much onion can a cat accidentally eat?

It takes a very small amount of onions to poison your cat or dog. Consumption of as little as 5 grams of onions in cats has resulted in clinically important hematologic changes. Onion toxicosis is consistently noted in animals that ingest more than 0.5 percent of their body weight in onions at one time. It is best if your cat does not consume any onion at all to avoid the risk of health issues.


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Beware of foods that contain onion.

Onions are in many of the foods humans eat every day. it's important to note that any foods containing onion or onion seasoning is harmful to your cat.


What to do if your cat eats onion.

Vomiting and diarrhea are the first signs that your cat may have onion toxicosis. It is not normal for your cat to have these symptoms. If your cat suddenly exhibits these signs, check around your home to see if she has accidentally eaten foods that lists onion as an ingredient.

If your cat is vomiting or experiencing diarrhea, seek veterinarian assistance immediately. Onion poisoning can be treated, but it's important to seek medical attention as soon as you notice symptoms.



Onions are dangerous for your cat to eat. If your cat eats even a small amount of onion, seek veterinary assistance immediately.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.