Foods your cat should NOT eat

Find out what cats must not eat.

Foods your cat should NOT eat

Who hasn't thought of giving their kitten some leftovers or a bit of food straight from the table? Well, this type of gesture, which seems insignificant and harmless, can actually cause very serious damage to the health of our four-legged friends. That is why, in this article, we've decided to explain what cats  must not eat.

When feeding our domestic cats, it is important that you always remember to respect their nutritional needs and remember that many foods that are good for us are very harmful and dangerous for them.

Unsuitable food can cause vomiting and diarrhoea in cats, but it can also be the cause of illnesses that often become chronic or acute  episodes that, in the most severe cases, can even cause death.

Dangerous foods for cats: what they must not eat

The most important thing to remember when feeding our four-legged friends is that it is never a good idea to give them leftover food.

Not only does it not meet the cat's nutritional needs, but it may contain substances that are not recommended for cats and may even be fatal if taken in large quantities.

So, let's see what cats are NOT allowed to eat:


Chocolate contains theobromine, a caffeine-like molecule that can be poisonous to cats.

This substance is absorbed much more slowly in cats than in the human body and therefore even small amounts can be dangerous.

Symptoms of theobromine poisoning include vomiting, diarrhoea, loss of appetite, muscle tremors, increased heart rate, dehydration, increased thirst and increased urination.

Tea and coffee

They can cause severe reactions in the heart and respiratory system, such as palpitations, tachycardia, shortness of breath and muscle tremors.

Onions, garlic, shallots, and chives

These foods should never be fed to cats because the presence of thiosulphate adversely affects red blood cell production and can lead to severe anaemia.

It is therefore important that the cat does not eat large amounts, but even unintentional consumption of small amounts may cause problems such as diarrhoea and vomiting.

Potato skins and green tomatoes

In this case, it is the presence of solanine that can cause digestive disorders or, in more serious cases, damage to the nervous system.

This substance is mostly found in the skin and leaves and tends to lose its harmful properties with cooking.


Avocado leaves, seeds and the fruit itself contain persin, a substance that can cause vomiting or diarrhoea in cats.

In addition, the high fat content can lead to other complications, such as gastroenteritis or pancreatitis.

Grapes and sultanas

Both can cause major kidney problems.

It is not yet clear which specific molecule is involved in the process, but consumption of grapes and sultanas is associated with acute kidney damage that requires immediate veterinary intervention.

Raw meat and eggs

As in humans, raw eggs and meat can transmit salmonella or E. coli, so it is important that these foods are always cooked before consumption.

Fish bones

Fish bones are very dangerous for cats because they can cause injuries to the digestive tract or even suffocation.

Milk and dairy products

The lactose contained in milk and milk products is difficult for adult cats to digest.

This is because, once they have stopped suckling, cats can no longer produce suitable amounts of the enzyme, lactase, in their intestines.

The main symptoms of lactose maldigestion are vomiting, wind and unformed stools.


Ingestion of alcoholic beverages or food containing even small amounts of alcohol can cause vomiting, diarrhoea, tremors, disorientation, respiratory problems, coma and even death.

Keep wine and other alcoholic drinks in safe places to prevent your cat from inadvertently coming into contact with them.


Although cats appear to be more resistant to the poisonous effects of xylitol than dogs, in some cases signs of drowsiness and vomiting may occur after consumption.

It should be noted that xylitol is sometimes used as a sugar substitute in the preparation of sweets.

Salty food

Food that is high in salt can cause high blood pressure and other liver diseases.

Dog food

If you also have a small dog at home, remember that your two four-legged friends have very different nutritional needs and cannot eat the same kibble.

In fact, dog food does not contain suitable amounts of protein, fat and taurine necessary for the well-being of the cat.

In the long run, this type of diet can lead to malnutrition and other serious health problems.

Nutrients that are NOT essential for cats

Now that you know what cats should not eat, let us discuss some nutrients that are not essential for cats. These include, for example, vegetable proteins, which are not suitable for cats.

In fact, cats are carnivores (so-called "strict" or "obligate" carnivores), which means they require a diet which is rich in easily digested, high-quality proteins, such as meat and fish.

Animal proteins have a more complete amino-acid profile than vegetable proteins and meet the cat's nutritional needs well.

We have covered this topic fully and in depth in the articles Vegetarian cat: why you should NOT feed your cat a vegan diet, Is your cat an omnivore or a carnivore? Here's what it should eat and Protein and cats: here's what you need to know.

Non-essential nutrients for cats also include carbohydrates.

In fact, cats are physiologically incapable of using them to their advantage and a diet rich in carbohydrates could lead to many diseases, such as excess weight, obesity and diabetes.

Don't forget to read our article on what cats should eat.

Remember that a correct, balanced diet is the first step in ensuring a healthy life for our four-legged friends.

The right diet for a cat is one that is rich in high quality protein, contains the right amount of fat and is never low in water.

Our After Dark line, for example, is the best option to guarantee the right amount of nutrients essential for their well-being.

After Dark products are complete and balanced, made from natural ingredients that are rich in proteins of high biological value, contain no preservatives, no added colourings and no cereals, so they retain an extraordinary taste and a very high nutritional value.

Watch what your cat eats: other dangers at home (and outside)

Finally, it is important to remember that there are substances and objects in the house that are very dangerous if the cat swallows them, even if unintentionally.

Medicines, cleaning products, but also plants and flowers can cause the death of our four-legged friends. That's why you should pay attention to your cat's behaviour and make your home safe for it.

Keep medicines and cleaning products in safe places where the cat cannot reach them and ask your vet which plants should not be kept in the house because they are poisonous to cats.

If you have a garden, also remember to keep your cat away from it for as long as necessary after you use fertilisers or insecticides.

Mouse, slug and cockroach traps are also poisonous: make sure your cat stays away from them at all times.

We hope you have found this article helpful to find out what cats should not eat.

If you have any doubts or questions, don't forget to talk to your vet, who will certainly be able to give you the best advice and suggestions.

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