What Should You Do If Your Cat Ate Onion? (Solved!)

I couldn’t believe it when I came home and found my cat, sparkles, eating green onions. She looked up at me with a surprised expression, like she had no idea they were bad for her health.

I was so mad! “How could you do this?” I said to her. She didn’t answer me because she didn’t know how to talk back, but the look on her face seemed remorseful enough.

Sound familiar? What is there to do if your cat eats onion, green or otherwise? In this article, we’ll tell you what we found out.

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Check For These Signs

Onion poisoning is serious in cats. The range of symptoms that present depends on how much onion they ate and the severity of their reaction to it. Some symptoms may show up immediately after ingesting the onion. Others may take a few days after they’ve eaten it.

Excessive Drooling

One symptom to watch out for is excessive drooling. It’s rare for cats to drool. If your cat produces a lot of salivae, it’s because its body is trying to wash out the onion.

Vomiting and Diarrhea

Vomiting and diarrhea are two other common symptoms of onion poisoning to look for. Vomiting occurs because the body is trying to expel toxins from the body. The same with diarrhea. It may also signify that your cat’s body is having problems digesting the onion.

orange tabby cat licking lips

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Pale Gums

Another thing to check is their gums. If they have pale gums, it could signify that they ate an onion and were poisoned. It cannot be easy to pull back the lips of your cat. You’ll want to be gentle handling them, especially if they’re not feeling well.

Physically Collapsing

A severe reaction is if they end up physically collapsing. They may become so lethargic or weak that they’re unable to stand. This signifies that your cat must be immediately taken to the vet or hospital.

Pain in Abdomen

They may also experience pain in their abdomen. You shouldn’t press on their stomach. However, even if gently running your fingers along makes them shy away, then it’s a good sign that something is wrong.

Elevated Heart Rate Or Respiratory Rate

Finally, you should check for an elevated heart rate or respiratory rate. Is their chest rising and falling rapidly? Are they breathing heavily? Their heart may be having difficulties. This is another sign that you must immediately take your cat to the hospital or vet.

white and orange cat licking lips

Potential Problems

The severity of your cat’s problem depends on how much onion it consumes. Some of the problems they may develop include:

  • Diarrhea
  • Vomiting
  • Gastrointestinal distress
  • Heinz body anemia
  • Hemolytic anemia

Diarrhea and vomiting are the most likely problems that your cat will have. They may experience some gastrointestinal sensitivity and discomfort, too. The best thing you can do for your cat in this regard is to keep giving them water. Diarrhea can make them dehydrated, which can only worsen the problem.

The biggest problem your cat may develop is Heinz body anemia. This is caused when the onion damages your cat’s red blood cells. It causes oxidative damage. With damaged red blood cells, oxygen cannot pass through the body.

As a result, your cat may collapse or grow weak. Certain organs may even fail if treatment isn’t given to them.

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My Cat Ate Green Onion

What To Do

One of the first things you should do is determine how many grams of onion your cat ate and what part of it the cat ate. For example, did it eat the bulb or the stem? Your cat might have milder symptoms if it ate the stem rather than the bulb.

If your cat ate a lot of fresh onion or even cooked, you might want to immediately take them to a vet or hospital to get checked over. Even if they seem fine initially, their reaction may worsen over time.

A cat that isn’t showing any symptoms should be monitored. Diarrhea and vomiting are to be expected. In this instance, keeping your cat contained in one area may be a good idea. Newspapers can be placed on the floor in the event of a mess. They should have plenty of access to water.

If the vomiting and diarrhea don’t clear up for two or three days, you should take your cat to the vet. Being unable to retain food or water can become lethal for your cat.

One of the biggest things you should watch your cat for is pale gums. This is a sign that your cat is experiencing Heinz anemia. To save their life, you should take them to your vet immediately.

onion rings in bowl

Do I Need To See The Vet or The Emergency Animal Hospital?

Mild reactions should be taken to your vet. They can help your cat reduce its suffering. They may also suggest easing their stomach ache and keeping them healthy while they vomit or have diarrhea.

At the very least, you should take your cat to the vet to get it checked out, whether they’re experiencing symptoms or not. Because their symptoms can sometimes take several days to emerge, getting your cat checked out can ensure they’re not developing anemia.

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If your cat has pale gums, you should take them to the hospital. This is a sign that Heinz’s body anemia is beginning. If you wait too long, then your cat may die. A hospital can help keep your cat alive with a blood transfusion.

Sometimes the cat may need to be given a scrub. If the onion touches their hair or skin, cleaning it is vital. They may develop a rash otherwise.

Safe Alternatives To Eat

Onions, leeks, and garlic are all part of the same family. That makes them all poisonous to cats. If you want to feed your cat vegetables, you should stick to carrots even though they’re carnivores.

Feeding them raw carrots can be a choking hazard. Cooked carrots are a better solution because they’re softer and smaller. There are many other types of vegetables cats can consume.

Can Cats Eat Onions?

Cats cannot eat onions. Onion toxicity in cats is poisonous to them. Like others in its family, onions can damage a cat’s red blood cells. When those cells are damaged, they can suffer organ failure.

Cats shouldn’t eat human food containing onions, stalk, cooked onion, or onion grass. Even onion powder or baby food with onions can cause an allergic reaction. If your cat eats an onion, you should try to induce vomiting. Taking your cat to the vet can ensure they’re induced safely.

Vomiting and diarrhea are the mildest symptoms you can expect if your cat eats an onion. Death is the most severe. If your cat eats onions, give your cat healthy food to prevent them from eating raw onions, onion powder, or other toxic foods.


Onions are toxic to cats. Eating even a small amount can cause them to become ill. Depending on how much they ate, your cat might have mild vomiting and diarrhea or become fatally anemic. If you suspect your cat has eaten an onion, immediately take it to the vet. Monitor them and keep them hydrated while they recover.

So if your cat has eaten onion, it’s important to take it to a vet immediately. There are safer alternatives that can prevent a cat eating onion, like cooked carrots or cat food that you can feed instead of onions. It’s best to avoid giving your cat any type of onion, including the leaves, stalks, and bulbs.

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We hope this article has helped you understand the dangers of onions for cats. Always watch your cat and take it to a vet if you think it has eaten something poisonous. Keep your cat safe and happy!