17 Surprising Ingredients Bad For Cats And Reasons To Be Cautious

This evolution from carnivores and hunters to your sweet, curious and playful kitty, have created a toll on their digestive systems, and sometimes your cat will eat something that his or her system will not process properly, which might damage your cat´s health on the long run
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what can cats not eat

What can cats not eat? Cats are obligated carnivores. They have evolved eating a diet of prey, which involves meat, bones, muscle, and fat. As they evolved, they also started to change their diet. Now they eat cat food we feed them, apart from the occasional mouse or bird they catch from time to time if they go outside!

This evolution from carnivores and hunters to your sweet, curious and playful kitty has created a toll on their digestive systems. Sometimes your cat will eat something that its system will not process correctly, which might damage your cat’s health in the long run.

No matter how much your furry friend gives you irresistible eye’s, looking to beg for what you eat. These are foods that cats can not eat. [1]

Alcohol

cat alcohol

We should never give anything containing alcohol to your cat, as this substance is very poisonous. But not only alcoholic drinks. Alcohol poisoning occurs when a cat ingests substances containing ethanol (like alcoholic drinks and liquid medications), isopropanol (such as flea sprays that are alcohol-based), and methanol (as in windshield washer antifreeze). Toxicity occurs rapidly as the alcohol is quickly absorbed into the cat’s system.

Cats that have consumed toxic amounts of alcohol will show symptoms shortly after the ingestion. These could be:

  • Vomiting
  • Disorientation
  • Inebriation
  • Loss of bodily control (ataxia)
  • Diarrhoea
  • The excitement which changes to depression
  • Difficulty breathing (dyspnea)
  • Loss of consciousness
  • Dehydration
  • Slow heart rate (bradycardia)
  • Seizures
  • Heart rhythm problems

If you suspect that your cat has ingested a product like rubbing alcohol, uncooked bread dough, or cough medicine, or if it is reacting to a shampoo, call your vet immediately. Symptoms can range from mild intoxication to severe.

The good news is that most cats wouldn’t drink alcohol, as the flavor and smell work as a repellent for them, but beware, holiday stress can cause your pets to act in ways they usually wouldn’t, like table surfing or digging in the trash for leftovers. So, avoid any dangerous situations for your pet by keeping any risky drinks out of their reach and making your guests aware of the dangers that alcohol, beer, wine, and many foods pose for pets. [1] [2] [3]

Coffee ( and caffeine in general)

Believe it or not, some cats like coffee! My cat also gets crazy with the smell of tea and wants desperately to leak the teaspoon. Mental note: don’t let them.

But not only is coffee dangerous for cats. Caffeine is a no-no for all felines. Includes coffee, tea, stimulant medication, energy drinks (what is your cat doing near a Red Bull anyway?)

According to the Pet Poison Helpline, It only takes ingesting a small amount to have toxic effects”. [4]

The dose of the caffeine varies depending on the size and weight of your cat. Drinking a splash of coffee is unlikely to contain enough caffeine to irreparably harm your cat, although it might make cats sick; however, if your cat were to eat coffee grounds, it could lead to severe caffeine poisoning. Too much caffeine can even be fatal for a cat. This is also true in dogs.  [5]

Common symptoms of the coffee ingestion can be:

  • Vomiting
  • Diarrhoea
  • Loss of muscle control
  • Tremors
  • Seizures
  • Collapse

The onset of caffeine poisoning is usually known by severe hyperactivity. If you know that your cat has ingested caffeine in any form, take it to the vet.

Be aware that the coffee also contains Theobromine and Xylitol, which is also toxic to cats.

When you finish your morning brew, make sure the grains of coffee is out of reach from your pet’s paw. Also, no matter how much your furry friend begs, do not let them finish your cold coffee. I know my cat would love to!

Chocolate

We all love chocolate in all shapes and forms, and it even has some sound effects reported in humans, like serotonin, which an increase in this elevates our happiness. Unfortunately, it doesn’t work the same way for cats. Stimulants are a no-go for cats.

Chocolate contains a chemical called Theobromine, which is poisonous to cats. Humans efficiently metabolize Theobromine, but the cat’s process is much slower, allowing it to build up to toxic levels in their system.

It also contains Xylitol, an artificial sweetener that is poisonous to cats.

The darker kinds of chocolate contain more quantity of Theobromine.

No amount of chocolate is safe for your cat, but with large amounts, Theobromine can produce the following symptoms:  [6]

  • Muscle tremors
  • Seizures
  • Irregular heartbeat
  • Internal bleeding
  • Heart attack. 

The onset of theobromine poisoning is usually marked by severe hyperactivity. Be aware that the smaller the cat is, the faster it will get affected.

If your cat has eaten a box of chocolates, take it to the vet immediately. Do not wait to see if it gets better. Early treatment will help your cat recover quicker and lower your costs.

Never give a chocolate chip as a treat for a cat, as it can seriously damage your furry friend’s health.

Onion or Garlic

Usually, your cat would avoid eating these ingredients naturally, but if your pet likes to eat everything they find, make sure that it can’t get to these foods.

According to the Pet Poison Helpline, a 24/7 pet poison control center, plants and vegetables in the onion family, such as garlic, leek, chives, contain Propyl Disulfide. This chemical destroys an animal’s red blood cells, causing anemia, which in severe cases can do serious damage to the internal organs. [7]

The most commonly known symptoms are:

  • Nausea
  • Vomiting
  • Diarrhea
  • Lethargy
  • Abdominal pain
  • Increased heart rate

If you see any of these symptoms in your cat after eating Onion or garlic, don’t hesitate to contact your vet.

Chewing gum and Candy

Most people would hide the chocolate, medication, teas, coffees, antifreeze from the reach of their furry friends because of the harmful effects of the Xylitol in their bodies. But has anybody thought about the chewing gum or the candy? If we take away the stickiness factor, it looks pretty harmless, right? Well, not quite. Never give chewing gum or candy to your cat. [8]

Chewing gum and candy also have Xylitol, an artificial sweetener toxic to cats. A single piece of sugar-free gum contains 0.3g of Xylitol. This means that a 4kg cat could start to have health problems after eating barely three pieces of gum. If this happens, your cat might have symptoms of hypoglycemia, which is a sudden drop of blood sugar. These could consist of:

  • Weakness
  • Lethargy
  • Collapse
  • Sometimes seizures.

If you suspect that your cat has eaten gum, please take them to the vet immediately, as you will need to start treatment to avoid the absorption of Xylitol immediately.

Dough

Some of us love cooking and making our food. And who doesn’t love an excellent homely made from scratch oven-baked pizza? Even if we are not in Italy, it is still delicious. Bad news for our four-legged furry friend. The pizza dough is extremely dangerous for pets. 

Dough rapidly grows after ingestion, which can cause life-threatening stomach distension and blockage. Also, the highest risk comes from the fermentation of the yeast in our cat’s stomach, which can lead to alcohol poisoning.[9]

A typical scenario is when we prepare the dough and leave it unattended over the counter all night, so it rises. We wake up to realize our beloved kitty has eaten it and is developing symptoms already. In that case, it is vital to take your cat to the vet immediately, as you will have to start treatment as soon as possible.

Ice cream (and any kind of cream)

Who hasn’t been on a warm day savoring a refreshing ice cream of your favorite flavor with your furry friend looking at you with those cute eyes begging for an opportunity to savor that cone? Who hasn’t thought that it would be no harm in sharing a couple of licks with your cat?

Well, you are not doing your cat a favor. Despite all the amount of sugar that goes with it, cats will not enjoy it at all. 

This goes against every stereotype we have on cats, but the truth is, almost all adult cats are lactose intolerant.

Symptoms that they will develop when eating ice cream will be

  • Diarrhoea
  • Vomiting
  • Gastrointestinal issues

And because of all the amount of sugar in it, they might end up having dental problems.

No matter how hot it is and how much you think they will enjoy it, don’t give your cat any ice cream or any cream (including milk). 

Milk and derivates

Who hasn’t always seen a cute kitten drinking from a bowl of milk? Or even an adult cat? This is one of the most potent stereotypes and associations there are regarding our furry friends. 

When we think about milk, we are thinking about cow milk and not the milk from the kitten’s mother, which is to be fed naturally until the weaning process is finished at 8-10 weeks. Kittens don’t need cow’s milk.

To digest lactose, the digestive system must contain an enzyme called lactase. As mammals, we have plenty of it at birth with our mother’s milk.

As we grow older, the cat’s and human’s bodies produce less lactase, which means less ability to digest lactose. This will eventually lead to lactose intolerance.

The truth is, the vast majority of cats are lactose intolerant. When a lactose-intolerant cat drinks milk, the undigested lactose passes through the internal tract, drawing water with it. The bacteria in the colon also ferment the undigested lactose, forming volatile fatty acids. All the above can lead to an upset tummy. The most common symptoms are:

  • Diaehrroa 
  • Vomiting

If this happens to your cat, bear in mind a visit to the vet for further recommendations.

Sometimes, a cat intolerant to lactose when drinking milk seems to tolerate better other derivates, such as milk or cheese. This is because different milk derivates might have different quantities of lactose. This doesn’t mean you can give indiscriminate amounts of cheese to your cat. It might still trigger a bad tummy on her. [10]

Grapes and raisins

Recently researchers and veterinarians have found that grapes, raisins, and currants can cause kidney failure in cats. Poison occurs in cats after ingesting seeded or seedless grapes, commercial or homegrown, red or green types, organic or non-organic fruit, and grape pressings from wineries. Also, foods containing grapes, raisins, and currants (such as raisin bran cereal, granola mix, trail mix, or baked goods) are potential poison sources.

Unfortunately, there is not a well-established toxic dose for these. Some kitties demonstrate more tolerance to the ingestion, and others become poisoned after ingesting just a few grapes or raisins.

Symptoms of grape and raisin poisoning are:

  • Vomiting, which is generally seen within 24 hours following ingestion
  • Lack of appetite
  • Lethargy
  • Possibly diarrhoea can be also seen within the next 12-24 hours. 

More severe signs are seen 24-48 hours after ingestion – often after acute kidney failure has already begun.

If you suspect that your cat has eaten grapes, raisins, or currants, please call the vet immediately. Don’t wait. [11]

Salt

Salt is bad for cats if they overeat it. For example, rock salt is left unattended over the kitchen counter or foods with too much salt on them. If they eat salt, they will have to counteract it by making several trips to the water station.

Cats and humans need sodium as part of the electrolyte balance, so small amounts are not entirely bad for your cat. Like most living things, cats need salt to help balance fluids and keep nerves functioning correctly. Most cat food you purchase has sodium in it, either naturally occurring from ingredients in the food or through added salt. So, salt, in moderation, is not bad for your kitty. In excess, however, it can lead to serious health complications and even death.

Too much salt can cause problems of 

  • Vomiting
  • Diarrhea
  • Lethargy
  • Swelling or fluid accumulation
  • Excessive thirst and urination
  • Tremors & seizures

Salt poisoning (hypernatremia) is life-threatening. If your cat consumes a good quantity of it, please get in touch with your vet for assistance. [12]

Nutmeg

Nutmeg -and spices in general- is considered a moderate risk for your cat in terms of toxicity. Your kitty would have to eat enormous amounts of nutmeg to have an impact on his health. However, this might be different depending on your cat’s age and health issues. 

Nutmeg contains myristicin, which is mainly found in the oil of the seed. It is toxic in cats and dogs when they eat around 5 grams of spice. 

Signs of poisoning include:

  • Decrease in body temperature
  • Dehydration
  • Vomiting
  • Decreased production of saliva
  • Increased heart rate
  • Muscle tremors
  • Disorientation
  • Seizures, and even death.

Symptoms can be seen as soon as 3-6 hours after the ingestion of the spice. It is important that if you suspect that your cat has eaten some amount of the spice, you contact your vet immediately. [13]

Avocados

Avocados have enormous benefits for our health, so you should incorporate them into your diet. But although they are perfect for humans, we cannot say the same for cats. They contain a fungicidal toxin called persin

According to the Pet Poison Helpline, persin is a mild poison for cats and dogs, which, if ingested by your pet in large amounts, can provoke the following symptoms:

  • Gastrointestinal problems
  • Trouble breathing
  • Heart issues

It will not kill your cat if ingested, and your cat definitely will have to eat a good amount of the flesh of the avocado for it to be toxic. Still, avocados would worsen certain medical conditions, so definitely avoid them if you can. You can substitute them with other foods that provide similar health benefits but without the persin.

Also, the skin and the pits should never be offered to your kitty.

Tuna

This could sound like another broken stereotype. Cats love tuna. That’s a fact, so how can it be bad for them? For sure, Lucy-Lu, my beloved kitty, absolutely loves tuna. With all the tricks she plays to be able even to get a bite, she deserves a medal. Of course, it never ends with a taste. Who is going to tell Lu that she no longer can savor one of her favorite foods?

Well, the good news for tuna lovers is that moderation is key to every pleasure in life. Tuna is one of this food that is good to have in small quantities, as it also has a lot of nutrients and benefits. 

A steady diet of tuna prepared for humans -canned or fresh- could lead to an unbalance, as your cat wouldn’t be getting all the nutrients they need. Also, too much tuna can lead to mercury poisoning, which symptoms include:

  • Dizziness
  • Loss of coordination and balance

Never give tuna to your cat as the main ingredient of their diet. Always treat it as an occasional treat

If your cat develops any of the above symptoms after eating fish, contact your vet.

Raw fish

Cats are fish lovers, and wherever there is a fishmonger, there will be cats waiting for their delicious treat. At least that is part of our collective imagination, right? 

Well, this is another of those foods where moderation is key. Consuming it in small quantities is probably ok. Still, varying amounts could trigger health issues in your cat due to mercury found in larger quantities, especially in bigger fish.

Also, like with raw eggs, raw meat and fish can have bacteria that potentially could trigger food poisoning. In addition, some fish like salmon, trout, sturgeon, or shad could transmit a parasite that can cause “fish disease” or “salmon poisoning disease.” [14]

If your cat gets any symptoms from eating raw fish, they will look like:

  • Vomiting
  • Fever
  • Big lymph nodes

If your pet shows any of these symptoms after eating raw fish or meat, immediately take him to the vet. 

Sugary Foods and Drinks

Cats don’t have sweet taste buds on their tongues. But the truth is they like it as much as we like it when it comes to sweets. They also can suffer from addiction to sugar, just like us. 

This explains how the brain works. When we eat or drink sugar, the nucleus accumbens area of the brain releases dopamine, which makes us feel good about ourselves. When sugar is consumed often and in increasing amounts, we reach some tolerance, which means we need more sugar to produce the same quantity of dopamine. That’s how sugar addiction is explained in both humans and cats. The only difference is that the cat is the only mammal we know that cannot taste it.

Unfortunately, like humans, cats suffer the same adverse effects after regular sugar consumption:

  • Diabetes
  • Obesity
  • Dental problems, etc

You need to be aware of the ingredients list of some food brands when it comes to sugar, as some of them will add more to create an addiction to that brand. Sugar also comes in many names and forms. 

Some of the most used in cat food are sucrose, caramel, and corn syrup. Sorbitol is a sugar alcohol derived from fruits and berries, but it can also be created synthetically. Beet pulp is the by-product of sugar production from sugar beets. Fructose is very sweet and is derived from fruits.

Although honey and molasses have often been said to have medicinal properties, keep in mind they are both still sugars.

Small amounts of naturally occurring sugars, such as those found in the foods that make up your cat’s foods, are not wrong. However, added sugars, especially those added to cat foods and treats, are not suitable for your cat. They can create an addiction and lead to health and dental problems.

Also, high consumption of sugar in cats can lead to diabetes. [15]

Bones

Bones present a health hazard for your cat. 

Chewing is a natural cat behavior, and bones are even full of minerals that are good for your pet. Still, you need to be aware of the fact that cooked chicken or even fish bones are harmful and even dangerous for cats, as they break and splinter into small, sharp pieces that can cut your cat’s mouth or digestive system. 

Broken pieces of bones can cause: 

  • Mouth and tongue lacerations
  • Choking
  • Broken teeth
  • Cuts and wounds in the mouth or on the tonsils
  • Vomiting and diarrhea
  • Severe constipation
  • An intestinal blockage that may require surgery.

The safest bet is never to give your furry friend anything on a cooked bone. Even the beef bones can break, causing the above symptoms. In addition to being unsafe, cooked bones are not as healthy as other bones, as most of the minerals and properties are stripped off in the boiling process.

Macadamia nuts

Who doesn’t like macadamia nuts? They are tasty, creamy, healthy, and a great source of protein. Also, they make a great ingredient when baking cookies, especially during the fall.

Although macadamia nuts are healthy for humans, it is not such a good idea for your pet. Your furry friend would only need to eat a small amount to experience terrible effects.

The symptoms in cats after eating macadamia nuts can be:

  • Diarrhea
  • Vomiting
  • Weakness in the back legs

In most cases, these adverse effects can be mild and manageable at home, but it has to be managed by a professional in more severe cases. Anyway, if you suspect your kitty has eaten macadamia nuts, you should contact your vet immediately.

Symptoms for a stronger adverse reaction might include:

  • Shaking constantly
  • High fever 
  • Unable to walk

If you see your cat vomiting, experiencing a lack of appetite, stomach pain, or decreased activity level within three days of eating macadamia nuts. In that case, you should contact your vet immediately.

What can cats not eat? What´s next?

The bottom line is that there are foods that are an absolute no-no for your cat, as per their high toxicity levels. Also, there are other foods which it’s ok if they eat a little bit and in moderation.

With cats being obligated carnivores, they should eat what they suppose to eat, but what they are not supposed to eat might take them down the road with health problems or even kill them.

Also, check what human foods are safe to give to your furry friend for more peace of mind.

In addition, why don’t you check our nutrition advice guidelines?

Dace Lace

Dace Lace

My name is Dace Lace. My love for my pets led me on a journey. Online forums and discussions opened more questions than answers. Also, I realized that there are more cat and dog owners out there looking for answers on the internet. However, some articles published was not backed up with science and I was uneasy about that, so I am putting my knowledge of nutrition and behaviour out there on this site

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