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Can cats eat onion? Why avoid feeding it to her?

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Onions are one of the more common spices. It’s very likely you have one in the fridge right now. If you have nothing to feed your cat, should you give an onion to her? Can cats eat onion? You must read this article if you don’t want to harm your feline friend.

There’s no denying that onions are very beneficial to humans. It can add flavor to any dish. It also has lots of antioxidants that fight free radicals, combat cancer, and decrease inflammation, among others.

But onion for cats is a different story altogether. According to Web MD, onions in all forms are harmful to our feline friends. It can cause gastrointestinal upset, and break down her red blood cells resulting to anemia.

While some food lovers insist a small dose won’t hurt, you would not want to take chances, would you?

Why is onion bad for cats?

Why is onion bad for cats? Well, this human food contains thiosulfate. This is an ingredient that can cause hemolytic anemia in cats, or red blood cell damage. Onion poisoning can result to affected red blood cells to rupture, and unable to carry oxygen.

You may wonder why humans aren’t affected by thiosulfate. The reason is that our bodies have the enzyme that can digest this ingredient. But cats, and even dogs, don’t have that ability. This explains why thiosulfate can be very bad for your cat.

In fact, it isn’t only onion that’s toxic to cats. Garlic, leeks, and chives which are part of the Alium species are known to cause the same health problem to our feline friends. These plants have oxidants that can affect the hemoglobin molecule in their red blood cells.

PetHealthZone reports that feeding cats with as little as 5g/kg of onions can cause hematologic changes in cats.

Some of the symptoms of hemolytic anemia in cats are:

  • Breathlessness
  • Vomiting
  • Diarrhea
  • Lack of energy
  • Poor appetite

It should also be noted that these symptoms won’t appear right away after your pet eats onion. Most of the time, it would take 2 to 4 days after your cat consumed the onion for the said symptoms to become apparent.

But let’s say your pet accidentally consumed onion because you left one in the kitchen. What would you do?

The best course of action is to bring your cat to a veterinarian immediately. Your vet may try to induce vomiting to decrease the cat’s absorption of the onion by administering a product.

All forms of onion are bad for cats

It should also be noted that all forms of onion are bad for cats. We’re not only talking of raw onions here. Fried onion rings and onion powder are harmful to your cats, in the same way as onions sautéed with mushrooms can affect your feline friends.

And yes, giving your cat pizza with onions and peppers is a really horrible idea.

In fact, there were several cases of cat onion toxicity recorded years ago. What was the reason behind these toxicity cases? It was found that onion powder was used in certain cat baby foods, which vets feed to kittens that were unwilling to eat.

Because of the said cases, onion powder is no longer used in baby cat foods.

Safety precautions

Due to the potential problems that onions can pose to a cat’s health, you should keep in mind the following safety precautions:

  • Wash and dry her coat if you catch her playing with onion
  • Don’t feed her with table scraps.
  • Don’t allow your cat to roam around your kitchen or table while you are cooking or eating.
  • Store your foods out of her reach. Keep your cabinets locked to prevent your cat from accessing your foods.
  • Never give in to your cat’s begging, no matter how badly she wants to bite your pizza.
  • Increase his activity. You can distract her by increasing her activity. Perhaps she needs more playtime?
  • Give her more frequent meals. There’s a likelihood that your cat can’t wait for her next meal, so she tries to get her hands on raw onion. You can deter her from eating the said food by increasing the amount of her meals.


Onions may have wonderful health effects for human, but it is completely harmful to felines. It contains thiosulfate, a toxic ingredient that has been linked to hemolytic anemia in cats.

Your cat should not have any business getting near a raw onion, or licking on a food with onion as its ingredients. Hence, you must not give her table scraps. You should also not allow her to roam around the kitchen. Onions are among the worst human foods that you can let your cat get her hands on.

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