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8 human foods that are poisonous to cats: What to avoid

human foods that are poisonous to cats: What to avoid
(Image credit: birgl / Pixabay )

Some foods present a hazard to our feline friends. While it's only natural you'd want to share your favorite foods with your kitty companion, doing so requires an understanding of which human foods are poisonous to cats. Allowing your cat to lick your plate or share a snack every now can be a positive bonding opportunity for both of you, but only if you can do so without putting your cat’s health at unnecessary risk. 

Feline digestive systems are more sensitive than ours, and some human food ingredients can actually cause organ failure, or even death, in cats. If you want to err on the side of caution, it is safest to stick to cat treats and cat food. If you want to know where to start, why not read our guides to the best wet cat food, the best dry cat foods and the best cat food?

If you would like to share occasional human food with your cat, though, it’s important to educate yourself on which items are safe or unsafe for your cat. Here are 8 human foods that you should never feed your cat...

1. Milk

cats drinking milk

(Image credit: Getty Images)

Many children’s books feature an image of a cat lapping up a saucer of milk. Unfortunately, those children’s books typically leave out the rest of the story!  

Cats are lactose-intolerant, which means that diarrhea and other gastrointestinal issues are a common aftereffect of drinking dairy products. While your cat may love milk, it’s best to refuse to share this particular item. 

Even at birth, kittens seldom drink their mother’s milk for more than a couple of weeks. Reintroducing them to milk in adulthood isn’t the best way to keep your cat healthy.

2. Chocolate

poisonous to cats

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Tempted to share a bit of cake or ice cream with your furry friend? Resist the temptation! You may know that chocolate is toxic to cats, but it can also be toxic to cats. Chocolate’s toxicity is caused by theobromine, and dark chocolate is especially bad, since it contains a higher percentage of theobromine.

Potential symptoms of chocolate toxicity include heightened thirst, vomiting, diarrhea, lethargy and muscle tremors. Longer term (24-72 hours after ingestion), hyperthermia and/or pancreatitis may result. Even if your cats seem really eager (cats like the taste of chocolate), resist the temptation. You won’t be doing them any favors by feeding them a toxic substance.

3. Alcohol

poisonous to cats

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Many inappropriate food choices can be forgiven as a matter of ignorance; you think you are doing what’s best for your cat, without being aware of the risk. However, the effects of alcohol on humans are pretty clear to see, so imagine the impact on a cat. Cats are not equipped with the right digestive setup to cope with alcohol ingestion. 

Obvious side effects include lethargy, labored breathing, and impacted coordination. Even beyond these obvious and possibly expected effects, there is the potential for a serious decrease in body temperature and blood sugar levels, as well as the potential for kidney and liver damage. 

4. Onions

poisonous to cats

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Leaving out scraps of unfinished dinner for your cats isn’t a great idea at the best of times, because these food scraps can contribute to obesity. However, sharing your leftovers is even more risky if those leftovers happen to contain onion remnants. Also found in some types of baby foods, onions (and most root vegetables, in fact) attack feline red blood cells, breaking them down and causing anaemia. 

Without adequate red blood cells to circulate oxygen, your cat can become severely lethargic. This toxicity can potentially prove to be fatal. It’s best to steer clear of garlic and onions when sharing food with your cats.  

5. Coffee

poisonous to cats

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We may rely on caffeine to power us through the day, but cats can most definitely do without it. Thanks to the presence of methylxanthines (another toxic chemical that is found in chocolate), coffee should always be kept away from cats. 

Small amounts of coffee shouldn’t cause serious harm, but larger quantities (such as those found in tea bags and coffee beans) can cause serious side effects in cats. These include hyperactivity, vomiting, tremors, and seizure. Cats may also experience elevations in their blood pressure and temperature, as well as heart arrhythmias.  

6. Eggs

poisonous to cats

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While cooked eggs contain valuable protein, giving raw ones to your cat is an absolute no-no. This is because they can cause salmonella or e. coli poisoning – which can be fatal in extreme cases – as well as inducing symptoms like vomiting or diarrhea, not to mention skin issues.

Raw eggs also contain a vitamin called avidin, which reduces the quality of cats’ fur. Raw food diets have become fashionable in some circles, but you should still be careful about what you include in your diet if you’re going down this route. With this in mind, avoid raw eggs.

7. Nuts

poisonous to cats

(Image credit: Getty Images)

Nuts contain plenty of vitamins that are beneficial to humans, but there is strong evidence that they should be kept well away from cats. Many of them – such as almonds, pecans, and walnuts – contain Omega 3 fatty oils that are hard for your cat to digest.

In turn, this can cause digestive problems. Vomiting and diarrhea are uncomfortable possible side effects, although in worse cases this can develop into pancreatitis. They might seem like a harmful bite-size treat to give to your cats, but as we’ve detailed, it really isn’t worth the risk. Stick to regular cat treats instead.  

8. Citrus fruits

poisonous to cats

(Image credit: Getty Images)

You may have seen some social media videos from a long time back about cats having an aversion to citrus fruits, particularly limes. This is probably a blessing in disguise, as pretty much all citrus fruits – not just limes – have the capacity to be poisonous to cats.

Like many of other foods mentioned in this article, citrus fruits can cause serious digestive issues, with vomiting and diarrhea being standout symptoms. Their natural aversion to citrus scents mean they are unlikely to get close enough to them to actually eat them, but there’s good reason to be wary nonetheless.

If in doubt, call the vet

To summarize, definitely do not give any of these foods to your cat – if you are currently doing so, please stop. Make sure any leftover meals containing these products are either disposed of, or kept firmly out of your cat's reach (if they're great at jumping then be even more careful).

If you think your cat may have consumed some of the above foods and/or are displaying symptoms consistent with having done so, please contact your local vet immediately.

Steve writes and proofreads buying guides, news stories and advice for Pets Radar, drawing on his lifelong experience as a pet owner. Currently sharing his house with two cats and a dog, he draws on the many highs and occasional lows of pet ownership he has borne witness to in his writing. He has worked in publishing for 15 years as an editor, sub editor and writer on a range of titles, such as SciFiNow, How It Works, All About History, Real Crime and Horrorville. You can follow him on Twitter @stevewright22