How Much Onion Will Hurt A Cat? Is It Toxic?

How much onion will hurt a cat? Discover the potential dangers of feeding onions to your feline friend and learn why it’s important to keep them away from this common kitchen ingredient.

Understanding the Toxicity of Onions to Cats

Onions, along with other members of the Allium family such as garlic, chives, and leeks, contain compounds that are very toxic to cats. These compounds, known as thiosulphates, can cause a condition called Heinz body anemia in cats. When ingested, thiosulphates damage the red blood cells in a cat’s body, leading to a range of health problems.

how much onion will hurt a cat

Cats are more susceptible to onion toxicity compared to other animals, as they lack a specific enzyme called N-propyl disulphide oxidase, which helps break down the toxic compounds found in onions. But how much onion will hurt a cat? Due to the lack of that specific enzyme, even small amounts of onions can have a significant impact on a cat’s health.

How Much Onion Will Hurt a Cat?

cats eat onions
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How much onion will hurt a cat? It only takes one gram per five pounds of body weight for cats to experience onion poisoning. For kittens, a single gram of onion is already lethal.

This happens because the red blood cells of cats are hypersensitive to the oxidants that onions contain. Such oxidant is the n-propyl disulfide, which is commonly found on allium species like onion, garlic, shallots, leeks, and the likes. This applies to both fresh and dried onions as well.

Ingestion of this herb can easily lead to hemolysis, a condition that destroys red blood cells. With fewer and fewer red blood cells circulating in a cat’s body, they will start to lack oxygen. In just a short amount of time, the cat will be in a critical condition. Note that onions are toxic to dogs as well.

Note that onion powder has a higher toxicity rate than fresh onions. Since the onion has been dried, it has become concentrated, therefore more oxidants.

Although a single bit of chopped onion will not make your cat drop dead, you should still avoid giving this food item. Each cat has a different sensitivity level. Some will tolerate onion better than other felines, while others will get sick easily. Also, note that some cats will take up to 24 hours upon the onion’s ingestion before showing symptoms.

Onion Poisoning in Cats

onion poisoning in cats
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Now that you know how much onion will hurt a cat, let’s talk about the symptoms of onion poisoning. There are the signs of onion poisoning:

  • Vomiting
  • Diarrhea
  • Pale gums
  • Weakness
  • Abdominal pain
  • Increased respiratory rate (panting, etc.)
  • Blood in urine
  • Skin irritations

Once you notice any of the symptoms above, you should rush your cat to the vet. Depending on your cat’s situation, the vet may try to induce vomiting to remove any undigested onions. Bloodwork will also be done to check the red blood cell level of your cat.

If the vet spots Heinz bodies, it’s a sign that your cat is already suffering from onion toxicity. Heinz bodies are formations on the red blood cells, which is due to oxidative damage. Hemolytic anemia will set in as well as lowering of oxygen levels as the red blood cells continue to deteriorate.

Nevertheless, cats who suffered from onion poisoning will see progress if given proper veterinary care. In some cases, the cat will be confined to the vet clinic for further observations.

Frequently Asked Questions

Can cats have Funyuns?

Funyuns is a brand of an onion-flavored snack. Funyuns are packed with onion powder, which is extremely poisonous to cats. Aside from that, it’s reeking with salts and artificial ingredients that will wreak havoc on any pet’s digestive system.

If you want to give your cat a tasty snack, stay away from junk food and onion. You can give it a slice of freshly peeled cucumber or some cooked oats instead.

Are spring onions poisonous to cats?

Spring onions are basically the green leaves growing from the bulb of the onion itself. It’s under the same Allium species, so it is not safe for cats. Spring onions will cause the same adverse side effects as onion bulbs, even though it has a lower oxidant level.

If you’re growing spring onions in your kitchen or garden, make sure that it’s out of your cat’s rich. You should treat the ingestion of spring onions the same way you’ll treat the bulb’s actual consumption.

Are sour cream and onion chips bad for cats?

Onion chips and sour cream are often flavored using onion powder. This is equally, or even more, poisonous than fresh bulbs. Aside from that, sour cream contains a lot of salts and dairy that will cause stomach upset in cats. Even though some of these snacks don’t contain actual onion, it’s still packed with salts and artificial flavoring.

Is smelling onion bad for cats?

Sniffing onions won’t hurt your cat, but it can cause mild eye irritation if they come too close. If you’re slicing some onions, it’s best to keep your cat away. Most cats will back off the moment they sniff the strong scent of onions. You should avoid your cat from having physical contact with chopped onions. The juices can easily cause skin irritation, especially on hairless breeds.

The smell of cooked onions is not toxic to cats. As long as you’re not giving the cooked onion to your kitty, there shouldn’t be a problem.

What should you do if your cat eats onions?

What should you do if your cat eats onions
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If you suspect that your cat has ingested onions, you should call the vet’s clinic immediately. Onion poisoning can be lethal, but it can be treated if detected right away.

Cats can die from eating large quantities of onion. But if your kitty only chewed a small bit or two, observing it for 12 hours should be enough.

Cats will become dehydrated after hours of vomiting and diarrhea. You should also increase the cat’s hydration. In this case your cat may need to be put in an IV drip to replenish the lost fluids. For worse cases, a blood transfusion might be needed to replace the damaged red blood cells.

Final words

How much onion will hurt a cat? Depending on your cat’s size and sensitivity, a single gram of onion might be enough to cause poisoning. You should never feed you cat anything with onions in it, regardless if it’s fresh, dried, or powdered.

Remember that your cat is a carnivore and will not benefit from the supplementation of onions. If your kitty ingested onions by accident, you should call the vet immediately.

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