Which foods are toxic to cats?

Some foods, while perfectly ok for human consumption, are toxic to our pets. Since cats are picky eaters, food poisoning is mainly a dog problem. However, some cats still like to eat stuff they’re not supposed to.

And pet food poisoning happens more than you would think. There is even a nice post from the Pet poison helpline about the top 10 pet poisoning increases during pandemic.

There are a few types of foods you should know about that are very toxic to cats. The treatment is mostly symptomatic since there are no antidotes available.

In the case of solid foods, if you manage to get your pet to a vet under ca 1.5 – 2h after the consumption, he can induce vomiting and remove stomach content. However, after those 2 hours inducing vomiting is no longer effective.

So please call your vet as soon as possible if you have a suspicion that your cat ate something he shouldn’t have.

So which common foods are toxic to cats?

While I am a veterinarian, this article is not intended to replace professional veterinary advice. If you have any medical concerns about your pet, consult your vet immediately. Always seek professional assistance if you are unsure of your pet’s health.

cat eating a cupcake

Onions, garlic, leek, and chives

These are all members of the genus Allium. And all of them all toxic for cats and dogs, even when cooked.

They contain organosulfoxides, which are metabolized to sulfur compounds. These sulfur compounds cause blood hemolysis, meaning they actually destroy red blood cells.

Already the ingestion of 5g/kg body mass can cause clinical signs.

Symptoms depend on ingested amounts and may appear 1 or even several days later.

Common clinical signs include vomiting, diarrhea, abdominal pain, loss of appetite, and apathy.
Anemia (not enough red blood cells) can lead to pale gums, rapid respiratory rate, rapid heart rate, jaundice, and dark urine…

There is no antidote and the animals need symptomatic treatment at a vet clinic.

Why is chocolate bad for cats ?

Chocolate contains methylxanthines, especially theobromine, and a small amount of caffeine. They are both toxic to cats and dogs. The amount of methylxanthines in chocolate or cocoa products varies. Unsweetened baking chocolate and cocoa powder usually contain more than 14 mg of theobromine per gram. Semisweet dark chocolate and milk chocolate often contain around 5 and 2 mg of theobromine per gram.

Theobromine and caffeine have each lethal dose of 100 – 200 mg/kg body weight, but severe or life-threatening clinical signs can develop already well below this dose.

Clinical signs usually occur within 6-12h after ingestion and may include vomiting, diarrhea, restlessness, tremors, and seizures.

Another often asked question – Is white chocolate toxic to cats ?

Well, technically, white chocolate isn’t really chocolate since it doesn’t contain cocoa particles. Therefore it’s considered to be an insignificant source of theobromine 🙂 However, the high-fat content might be a problem.

Coffee and caffeinated beverages

Coffee and caffeinated beverages and products contain caffeine and theobromine. While one or two licks probably won’t cause a big problem, ingestion of a higher amount can lead to vomiting, hyperactivity, restlessness, elevated heart rate, tremors, seizures, and even collapse.

Are grapes bad for your cat?

Grapes and their dried products (raisins, sultanas, currants…) are nephrotoxic, meaning they can cause kidney damage and even kidney failure.

The exact mechanism is still not very well understood. The toxicity is well reported in dogs, cats are in a bit of a grey area. To make matters even more complicated, the toxicity doesn’t seem to be dose-dependent. Some animals develop symptoms after a few bites, others can tolerate higher amounts.

However, I would certainly recommend contacting your vet immediately if your cat ate grapes or grapes-containing products (juice, raisin paste…). In case of a potential kidney failure you just don’t want to wait for the signs.

Alcohol (Ethyl-alcohol and ethanol poisoning in cats)

Ethanol and ethyl-alcohol can be found in a variety of products (alcohol beverages, but also paint, medications, and mouthwash…). Ethanol poisoning usually occurs after ingestion of alcoholic beverages.

I’ve seen videos where the owners found it hilarious and filmed their “drunken” animals. However, alcohol poisoning can very easily lead to coma or death. Symptoms include vomiting, diarrhea, tremors, disorientation, trouble breathing, and loss of consciousness. The onset is usually within 1 hour and from then on it can get very ugly very fast.

Raw dough

The raw dough contains special yeast, which metabolizes sugars to ethanol. So your cat actually gets alcohol poisoning. Furthermore, yeast can cause extensive gas production in the stomach and abdomen, which is very painful and can be also life-threatening.

Now, here are 2 more things people get confused about. They are not really toxic, but I feel like we should talk about them a bit. I get asked these 2 questions quite often and I know there are some very common misconceptions.


Are avocados toxic for cats? Avocado contains persin, which can be deadly to some (pet) birds or large animals (cows, horses…). Cats are very rarely affected by persin, however, they can develop pancreas inflammation due to high fat content.

And finally – what about milk? Is milk bad for cats?

It’s a popular myth that cats need milk. The truth is they don’t. Especially not cow’s milk.

Cats are like humans, kittens drink mother’s milk and have no problems with lactose (the sugar in milk). However, as they get older their ability to digest it declines rapidly. So a normal adult cat is actually “lactose intolerant”. While some cats still can digest milk, you might end up with a cat with severe diarrhea, vomiting, and stomach pain. So it’s better not to risk it. Not to mention it’s full of fat.

Your cat needs water and a well-balanced diet. That’s all 🙂

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    • Monika

      I’m sorry to hear that. I would strongly advise you to take your cat to a vet. If she has diarrhea for longer than a few days, she needs to be checked out. It’s dangerous not only for her but for you as well. It sounds like a serious problem, it might be an infection or a parasitic infestation, which can be passed from animals to humans… Please take her to a vet as soon as possible.

  • dana

    I had no idea milk could cause diarrhea in cats! We always used to give kittens milk as a treat – I will make sure to share this knowledge with my cat-loving family! Thank you for sharing 🙂

    • Monika

      Hi Dana, not all cats are lactose intolerant, but a lot of the are. And there are better treats your kitten can enjoy even more than milk (our cat loves everything fishy 😊).

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