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Can Cats Eat Onions? Are Onions Toxic For Cats?

Can Cats Eat Onions? Are Onions Toxic For Cats?

Is any type of onion safe for your cat to eat? You may have exposed your cat to onions at some point, or it may have sneaked a bit. Although eating a bite-size amount of onion will most likely not cause any damage to your cat, it is not recommended for cats to eat.

In short, no, cats should not eat onions. A tiny amount of onion might not hurt your cat or cause any apparent symptoms. But eating even a small amount can cause dangerous side effects. Onions are toxic for cats, and their consumption can lead to a series of health concerns.

Onions are super popular due to their flavourful quality and associated health benefits for humans. For your cat, though, the story is very different. Asking your veterinarian is always a good idea when considering which human foods you can give your cat, or if you should give it any at all. Onions and cats do not mix well, and we will explain why.


Why Shouldn’t Cats Eat Onions?

Onions have significant health benefits for humans. They are composed of sulfur combinations which cause their strong smell and taste. They have anti-inflammatory properties, help our cardiovascular system, and help to prevent cancer, among other benefits.

In the case of our feline friends, onions don’t offer them any nutritional value. The best choice is always to keep your cat away from them. Onions are toxic for cats and can be very harmful to their small bodies.

Cats have sensitive digestive systems, which can exacerbate gastrointestinal problems with the consumption of onions. Onion poisoning can easily happen if your cat overeats onions.

The most dangerous concern of cats’ exposure to onions is that they can develop hemolytic anemia. Eating onions in great amounts can also inhibit the proper functioning of a cat’s red blood cells.

Any form of onions – cooked, dehydrated, fresh, or table scraps with some level of onions in them, can pose a threat to cats’ health. However, cooked onions are a bit less harmful than raw onions.

How Much Onion Is Toxic For Cats?


Onions are known to have toxicity levels that can cause adverse side effects on animals. This Allium family plant contains thiosulphate and glutathione toxins. There are responsible substances for causing toxicity to cats and other species.

The more onions a cat consumes, the more at risk it will be. A small amount of 5 g/kg or two grams per pound of bodyweight of onions consumed by cats has resulted in hematologic changes in their bodies. A small amount of 0.5% of their body weight is all they need to get intoxicated. A significantly high dosage of around 600-800g or divided over a few days can damage red blood cells and develop Heinz body hemolytic anemia.

Heinz bodies are clumps formed inside the erythrocyte cell membrane due to damaged hemoglobin divisions. These clumps can be seen under a microscope; thus, the name Heinz body anemia originated.

More than any other species, cats are highly susceptible to damage caused by eating onions. As early as 12 hours after onion ingestion, cats can develop anemia. Still, it can take two to five more days for symptoms to show.

The good news is, anemia is a reverse condition as long as there isn’t another health issue that may worsen it. As the development of anemia is quick, it is best not to take the risk and keep your cat away from this common vegetable.

Onions, in any amount, aren’t safe for cats. Even in minor quantities or just a tiny portion of another type of meal, avoid them entirely.

Your cat might eat a tiny amount of onion and not get sick, but keep in mind that onion toxicity builds up in your cat’s system. If your cat is eating onions regularly, there is a possibility that they become intoxicated later on.

What Side-Effects Can I Expect If My Cat Eats Onions?

Signs like vomiting, diarrhea, abdominal pain, lack of appetite, depression, excessive drooling, elevated respiratory rate, and dehydration are common among cats who have eaten onions in high amounts. More severe signs like loss of red blood cells, pale mucous membranes, fast respiratory rate, trouble breathing, lethargy, dark-colored urine, jaundice, weakness, and rapid heart rate may take a few more days after the consumption to arise.

What Should I Do If My Cat Eats Onions?


First off, you should try to find out the number of onions your cat may have eaten. Call your veterinarian and explain the situation. Ingestion of a small quantity will not always mean a problem for your cat. But, if your cat consumed a more significant amount, it may be necessary that you take it for a check-up or directly to the emergency room.

In an urgent situation, your veterinarian may provoke vomiting in your cat to eliminate some of the toxicity that is still unprocessed from his gastrointestinal tract. Do not try to do this at home yourself. Blood transfusions may even be considered in extreme cases.

Some symptoms show up after a few days of a cat eating onions, so pay attention to their behavior for the next couple of days.

Do Cats Like Onions?

Each cat is unique, and they may each go crazy over something different in our pantry. Your cat may not have even tried onions before, but just the smell when you are chopping some up may have them asking for a piece.

Some cats have fetishes over some human foods like different kinds of vegetables. Even though house cats don’t need to hunt, they carry a very high sense of smell detection. Enticed by novelty, cats are most likely attracted to the strong smell of onions.

It is rare for cats to want to eat raw onions. They will probably meow to get some cooked onions with butter or other tasty food seasonings to awaken their senses.

How Can I Prevent My Cat From Eating Dangerous Foods?

Human food is not for cats. If you always have this present, you should try your best to keep potentially harmful foods away from your cat.

If the necessity of giving your cat a treat keeps you up at night, a specific cat treat, occasionally, will be much better. The market is full of exciting and tasty snacks for your furry pal. Even though they might love them, you should not give treats to your cats freely, as they count in your cat’s daily calorie intake.

Final Words

So, how much onion can your cat eat? None is the safest choice. Onions should never be part of your cat’s diet because they can cause serious side effects that can even become fatal. Your cat’s size and sensitivity are two things to take into account. The tiniest amount can hurt your small cat. Any onion should be avoided, including meals that contain some onion amounts.

There are no substances in onions that can benefit your carnivore cat whatsoever. Suppose your cat is one to drool over onions; try to experiment with treats specially made for cats that will get it as thrilled as onions do. Every pet’s diet should be respected to ensure they stay in their best nutritional state.

You may want to avoid your cat developing anemia from onion toxicity. This side effect is severe and sometimes fatal.

Reach out to your veterinarian for further recommendations if you suspect your cat has been eating onions. We wish your cat a healthy and happy life at all times!