22 Foods That You Should Not Be Feeding Your Cat

Updated: August 9, 2022 by Kristen Chapple

When I’m sitting at the dining table with my cat staring up at me longingly with her big eyes, touching a paw to my leg to get my attention, the urge to feed her a little something off my plate can be hard to resist. But it is important that we do indeed resist.

Not only is human food high in calories, and therefore can quickly lead to an overweight kitty, there are also many foods that we take for granted in our diet that are extremely dangerous to cats, even toxic or lethal.

In general, cats are better off eating their own specially formulated foods that shouldn’t contain any nasties that are bad for them and are balanced to include all the nutrition that they need, as their dietary needs are quite different from human dietary needs.

While your cat may enjoy treats, what they need is for you to take care of their health. So know what they should and should not be eating with our list of 22 foods that you should not be feeding your cat, and why.

List of Foods That You Should Not Be Feeding Your Cat

1. Liver – In Moderation

Liver is actually very good for your cat, containing many of the vitamins and amino acids that they need to thrive. Also, liver is part of a cat’s natural diet in the wild, where they will catch and eat the whole animal, including muscle, liver, bone, skin, and all. But that is the key, in the wild, liver would form only a moderate portion of their diet. A diet that is too high in liver, as opposed to muscle meat, can be toxic, specifically causing vitamin A toxicity. Symptoms include deformed bones, bone growth on the elbows and spine, and osteoporosis. So, while it is good to include liver in your cat or kittens diet, don’t be tempted to pick up a bag of chicken livers at the local butcher for their bowl.

2. Tuna – In Moderation

Cats love the taste and smell of tuna, and it is perfectly fine to feed them tuna once in a while. However, it should not be a staple in their daily diet. Tuna is high in mercury, so eating a lot of it presents a cat with a high risk of mercury poisoning. Feeding cats human grade tuna as an alternative isn’t great either. The canned variety generally contains too much sodium for cats. The type in oil has too much fat. The freshly cooked stuff doesn’t have all the vitamins and minerals that they need, so if eaten regularly it can lead to malnutrition. Basically, cats should be eating tuna only in moderation (as should their humans).

3. Fat Trimmings – Avoid

While you would think that scraps of uneaten meat off your dinner plate would be relatively safe for cats, as consummate carnivores, unfortunately, they are not. Usually, your leftovers include fat that you have trimmed off the meat and bone and decided not to eat. While fat is not inherently bad for cats, the kind of concentrated fat that they would get from this kind of ‘treat’ can cause serious intestinal upset, which you will know about thanks to the accompanying vomiting and diarrhea.

4. Bones (Cooked) – Avoid

Another reason not to feed your cat leftovers from your meat dinner is bones. While bones are a normal part of a cat’s diet in the wild, where they will kill an animal and eat it whole, these are raw bones. Raw bones have a relatively soft consistency, and cats can break them up with their teeth and digest them. When bones are cooked, they become brittle and instead of breaking up into edible pieces, they crack into shards which can cause obstructions or punctures in your cat’s throat and digestive system.

5. Milk and Cheese – OK, but a common allergen

Growing up, the image of a cat lapping milk out of a bowl embedded itself in my mind as normal cat behavior, so when I become a cat parent I was surprised to learn that many cats are lactose intolerant. So cats, like people who are lactose intolerant, cannot digest the lactose in milk and cheese, which results in vomiting and diarrhea. If your cat is not lactose intolerant, they may love milk and cheese (my cat loves cheese), but it should still be fed to them only in moderation, as it is high in fat and cholesterol so it can be bad for their weight. There is also lactose-free cat milk available if you rely on milk as a source of hydration for your cat but worry that they might be intolerant.

6. Raw Meat – OK with Proper Preparation

When you look at lists of foods that cats can’t eat, you will often see raw meat on the list, which is a surprise, since this is what cats naturally eat in the wild. The fear with raw meat is bacteria such as salmonella and E. Coli. But this is actually more of a threat for the human preparing the food than the cat diners, who have a higher tolerance to this kind of bacteria than humans. Nevertheless, when feeding your cat raw meat, be sure that it has been prepared in a safe and clean environment.

7. Raw Fish – Moderation

Fish again is something that cats eat naturally in the wild, but is commonly found on lists of foods that cat should not eat. This is because many types of fish, including anchovies, sardines, herring, carp — and shellfish too, like oysters, mussels, and clams — contain thiaminase enzymes, which can break down and lead to thiaminase deficiency in cats. This interferes with their ability to use vitamin B, which can, in turn, result in serious neurological problems. For this reason, raw fish should be eaten in moderation, as a complement to a major meat diet, to avoid excess thiaminase. The same risk does not exist with cooked fish as the cooking process renders these enzymes harmless.

8. Raw Eggs – Avoid

Raw eggs are another one to avoid because of the risk of salmonella and E. Coli, which are difficult to guard against when it comes to eggs.  But in addition, the protein found in raw egg whites contains avidin, which can interfere with cats’ absorption of the biotin, which in turn blocks a cat’s ability to use other B vitamins. This is often first evident in a rough coat and dry flaky skin.

9. Onions, Garlic, and Chives – Avoid

While a little bit of onion, garlic, or chive in a sauce is unlikely to cause your cat any problems, they are best avoided in large quantities. All members of the onion family can break down a cat’s red blood cells and lead to anemia if eaten in sufficient quantities. Chives, in particular, can also cause gastrointestinal problems, which means that it is not an ideal ingredient for cat food, though you will sometimes find it as a trace ingredient. If you have chive plants in your kitchen or garden, best keep an eye out and ensure your cat is not snacking on them.

And while there are no studies that determine whether ginger is safe or not, it’s best not to give your cat any until it’s proven safe.

10. Mushrooms – Avoid

While not all mushrooms are dangerous to cats, knowing which are OK and which are incredibly toxic can be very difficult, so they are best avoided altogether. Wild mushrooms can be particularly harmful and can induce vomiting, diarrhea, drooling, and eventually liver damage. Unfortunately, symptoms usually only appear six to 24 hours after ingestion, so by this time the mushrooms are firmly in your cat’s system, minimizing treatment options.

11. Grapes and Raisins – Avoid

The evidence here is unclear, so it is a case of better safe than sorry. There is good evidence to show that dogs can suffer kidney failure from eating grapes and raisins. The evidence that the same is true for cats is currently only anecdotal but doesn’t seem worth the risk. Reported symptoms include vomiting and hyperactivity. So keep grapes and raisins out of reach of kitties that like to steal treats from the table.

12. Green Tomatoes and Potatoes – Avoid

Unripe tomatoes and potatoes contain a poisonous alkaloid called Glycoalkaloid Solanine, which can cause your cat major gastrointestinal problems. Both of these are often ingredients in dry cat foods but aren’t something that you should worry about in this context. Cat food manufacturers use ripe tomatoes and potatoes, and they are also cooked, transforming the alkaloid and rendering it harmless.

13. Nuts – Avoid

You might think that nuts make a good addition to a cat’s diet as an excellent source of fiber, protein, and healthy fats, but not so fast. Some nuts, such as macadamias, are poisonous to cats. While other nuts, such as Brazil nuts and almonds aren’t inherently dangerous, but they are high in fat and calories. Just a few nuts can push your cat significantly over their daily calorie intake and the high concentration of fat can cause diarrhea and vomiting.

14. Caffeine – Toxic

Sharing a cup of tea with your cat should only ever be in the metaphorical sense! Anything that contains caffeine, including tea, coffee, soft drinks, and chocolate, should be off the menu as far as your cat is concerned. Small quantities can give your cat rapid breathing, heart palpitations, and muscle tremors. In large quantities, caffeine is fatal, and there is no antidote. As well as looking out for your cat stealing a sip from your cup, make sure they do not accidentally eat coffee beans or grinds.

15. Chocolate – Toxic

As well as containing caffeine, chocolate also contains theobromine, which again can cause cats heart problems, muscle tremors, and seizures. It is in all varieties of chocolate, though dark chocolate and unsweetened chocolate have the highest concentration. Fortunately, in general, cats won’t be tempted to eat chocolate on their own, so it is up to you not to coax them to share a treat with you.

16. Xylitol – Toxic

We all know that artificial sweeteners are bad for us as humans, so it is no surprise that the same is true for cats. It is found in many processed foods for humans, so these should never be shared with feline friends. Consumption can cause a severe drop in blood sugar levels which can lead to seizures and convulsions and even death by liver failure if it is consumed in large enough quantities. Do something good for both your and your cat’s health and expel these kinds of processed foods from your home.

17. Alcohol – Toxic

Even if you consider yourself a lightweight, you are nothing compared to your cat! As little as one tablespoon of alcohol can cause them serious brain and liver problems, and just two teaspoons of whiskey can send a five-pound cat into a coma. While you might think it is fun to give your cat a small sip while sharing a drink with friends, it could be lethal.

18. Yeast Dough – Toxic

If you are a baker and your cat likes to steal scraps, then be extra wary when it comes to yeast dough. Just as yeast dough rises in order to make the fluffy bread that we love, when cats ingest the dough it can expand in their stomachs, stretching their abdomen and causing serious pain. Moreover, when the yeast ferments, it can create alcohol, which we have already talked about as being deadly poisonous to cats.

19. Dog Food – Avoid

While dog food and wet cat food may seem similar, they are in fact quite different. Principally dogs can live off a vegetarian diet and therefore usually have much more plant product in their feed. Cats, on the other hand, have evolved as consummate carnivores and many of the essential compounds that they need they are only able to produce from eating animal-based protein.

They cannot substitute this animal-based protein for plant-based proteins as dogs and humans can. This means that a diet of dog food will quickly leave your cat with malnutrition. If you catch your cat stealing food from your dog’s bowl once, it is nothing to really worry about. However, don’t let them make it a habit. They shouldn’t be filling up on food that is not right for them.

20. Treats – In Moderation

While cat treats certainly aren’t toxic for your cat, they are one of the main causes of cat obesity as they are generally high in calories. The average house cat only really needs to eat about 200 calories a day and most cat parents are already overfeeding their pets with normal food. Add treats into the mix and you may quickly find yourself with a cat with a serious weight problem. And just like with humans, it is much easier to put it on than lose it.

21. Your Medicine – Toxic

While it may seem obvious to say that you should not be giving your cat your medicine, it is surprising the number of cats that are poisoned in this way. We know that children need smaller medicine doses than adults, so imagine how small a dose your seven-pound cat would need of that medicine.

Moreover, common human medicines such as acetaminophen and ibuprofen can be deadly to cats even when consumed in only small quantities. Keep your medicine cabinet both child and cat-proof.

22. Seeds and Spices – Toxic

Pits and seeds from vegetables and fruits tend to have substances in them that are toxic to cats. You should avoid herbs like mint, and spices such as cinnamon.

What to Do If Your Cat Eats Something They Shouldn’t

Chewing on rose petals, a few slices of cucumber, or a celery stick would be harmless, but if you suspect that your cat has eaten something that they shouldn’t, take them to the vet right away as the cure depends on what they have ingested. Try and figure out when they ate the offending item and how much of it they have eaten. If they haven’t eaten much, it may be a matter of passing a few uncomfortable days.

If they have got their paws on a whole bag of wild mushrooms, they will probably need to have their stomach pumped. Also, keep track of their symptoms such as vomiting and diarrhea. And don’t complain about the cleanup—in this case, it is a matter of better out than in!