Onion and garlic toxicity in cats

Onion and garlic toxicity in cats is not common; however, symptoms can be severe so it’s important to be aware of the risks. Cats are a lot more sensitive to poisoning compared to dogs. Recovery rates from onion and garlic toxicity are high without any long-term problems.

Contact a vet immediately if your cat has eaten onions or garlic, no matter the quantity. Your vet will determine if further treatment is necessary, depending on how much was eaten. Any age of cat can develop poisoning. The most common symptoms are due to irritation of the mouth and tummy.


What is onion and garlic toxicity in cats?

Onions and garlic are part of the Allium family of plants, which also includes leeks, chives and spring onions. These can all cause illness in cats when ingested.

  • Onions and garlic are a kitchen staple, found in many meals, baby foods, soups, seasonings, sauces, and even human supplements. They are poisonous when raw or cooked.
  • Powdered and dried forms tend to be more concentrated so they are more likely to cause illness.
  • Garlic is thought to be the most potent of the Allium family. It’s five times more toxic than onions.
  • Alliums contain toxins called disulphides and thiosulfanates. These toxins can damage the red blood cells in the body, leading to anaemia.
  • Signs of garlic toxicity usually start within 24 hours if a large amount has been eaten. Signs can sometimes be delayed for up to a week, especially when eaten in smaller amounts.
  • Cats should not be allowed to eat any garlic or onion at all.
  • In some cases, onion and garlic toxicity can be fatal in cats.


How much onion and garlic causes toxicity in cats?

Cats are much smaller than dogs and are unfortunately more susceptible to onion and garlic toxicity; however, the exact amount is not known. Some studies have shown that for garlic, ingestion of a single clove can cause severe illness. For onions, ingestion of more than 5g/kg bodyweight can lead to anaemia but even as little as a teaspoon can cause signs of illness. These are estimates and all cats can react differently. It may take a lot less or more for signs of poisoning in some cases.

Call us now if your cat has eaten onions, garlic, or anything else that may be poisonous. Our Joii vets can help you with the next steps. We are available 24 hours a day.


Symptoms of onion and garlic toxicity in cats

The symptoms of onion and garlic toxicity depend on how much is eaten. A larger quantity or a more concentrated form (like powder) causes more severe symptoms. In cats, the symptoms tend to appear after 2-4 days.

Common signs include:

Eating larger amounts can lead to damage to the red blood cells. Symptoms include pale gums, breathing problems, and red urine. Find out more about anaemia in cats. Red blood cell damage can lead to kidney disease.



Are some cats more at risk of onion and garlic toxicity?

  • Cats that scavenge and curious kittens are more likely to ingest onions or garlic from the floor or rubbish bin.
  • Breeds including Burmese, Oriental shorthair, Siamese and Turkish Angora have been shown to be more susceptible.



How is onion and garlic toxicity diagnosed in cats?

Diagnosis is usually based on the history and clinical signs. It’s important to let your vet know if your cat has eaten any onions or garlic and how much. Tests that may be needed include:

These tests are usually repeated after a few days, as the damage may not appear until up to a week later.


Vet treatment

Vet treatment for onion and garlic toxicity in cats

If caught early, usually within 2-3 hours, your vet will most likely give your cat an injection to make them vomit. This helps to remove as much of the toxin as possible. Further treatments depend on the severity of the signs and may include:

  • Hospitalisation for fluids and monitoring
  • Anti-sickness medication
  • Tummy protectants
  • Activated charcoal to prevent absorption of the toxin in the tummy
  • Blood transfusion and oxygen therapy if severe anaemia is present


Home treatment

Home treatment for onion and garlic toxicity in cats

It’s important to contact a vet if your cat has eaten any plant in the Allium family before attempting any home treatment. In mild cases, it may be possible to monitor at home.

  • Make sure your cat is drinking normally
  • Monitor their urine and stools for anything abnormal (such as a change in colour or consistency)
  • Feed small meals of bland food, such as eggs and rice, if they have vomiting or diarrhoea
  • Use a probiotic to help improve the stools


Tips on how to prevent onion and garlic toxicity in cats

  • When cooking, make sure to clean up any spills on the floor straight away
  • Don’t leave any leftovers on the table or kitchen counters
  • Make sure your rubbish bin is secure and never leave your cat home alone with access to it
  • Prevent access to any dangerous plants in the garden by using a fence
  • Avoid giving your cat any human food; stick to cat food and treats specifically made for them

When to worry

When to worry about onion and garlic toxicity in cats

Seek help from a vet if your cat:

  • Has pale gums
  • Has blood in their urine
  • Is collapsed or having seizures

Call us and speak to one of our Joii vets if your cat:

  • Has possibly eaten garlic or onion and you are unsure what to do next
  • Has mild vomiting or diarrhoea


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