Food Not To Feed Cats: 27 Toxic Foods You Should Avoid

Struggling to understand which human foods you can give your cat? Here are 27 toxic foods that you should avoid.

Food Not To Feed Cats: 27 Toxic Foods You Should Avoid

Hi. I’m James, and I have the pleasure of being a dog owner as well as a cat owner too! I’ve been lucky enough to have a pet nearly all my life.

Understanding your pet’s nutritional needs and what food not to feed cats is often an impossible task when researching on the internet.

Many websites will tell you inaccurate information with no clear scientific evidence to support their claims. So I thought I would find out exactly why some of these foods are bad for your cat and how they affect them. 

After several hours of research, I’ve found you 27 foods that your cat should avoid at all costs. 

A registered vet has proofread this article to ensure the information I have given you is truthful and accurate.


Tomatoes contain a toxic glycoalkaloid called Glycoalkaloid Solanine, which is found in the stems and leaves of the plant.

This alkaloid causes gastrointestinal symptoms, including; hypersalivation, depression, weakness, or slow heart rate. It can result in death if untreated.

If you suspect your cat has consumed tomatoes, speak to your vet immediately to identify if treatment is needed.

The ripe fruit is non-toxic, according to the ASPCA. [1,2]


Onions are part of the Allium plant family, which contains sulfoxides and aliphatic sulfides. These compounds are absorbed by the gastrointestinal tract, resulting in methemoglobinemia in cats. 

Methemoglobinemia (MetHb) is a blood disorder in which an abnormal amount of methemoglobin is produced. Hemoglobin is the protein in red blood cells (RBCs) that carries and distributes oxygen to the body. Methemoglobin is a form of hemoglobin.

With methemoglobinemia, the hemoglobin can carry oxygen, but is not able to release it effectively to body tissues.Medline

Methemoglobinemia eventually causes anemia in cats, leading to breathing difficulties, elevated heart rates, weakness, and even death. 

There is no antidote to this kind of poisoning, so contact your vet immediately if you suspect your cat has consumed onions.

Cats are considered more sensitive to onion poisoning compared to other animals. [3,4,5]


Alcohol contains a toxin known as Ethanol disrupts the nervous system’s GABA receptors. This is why you feel ‘drunk’ when you consume alcohol; the same principle applies to cats. 

In addition, beer contains an ingredient called Hops, leading to a rise in body temperature (also known as malignant hyperthermia) in cats.

Common signs of toxicity include; drooling, weakness, vomiting and retching, incoordination, or a decreased breathing rate. This can eventually lead to respiratory difficulties, seizures, and even death. [3]


Similar to onions, garlic is part of the Allium family. We have already discussed the dangers of this plant family in cats. [3,4,5]


Like dogs, cats are lactose intolerant. Therefore, they cannot digest dairy the same as humans can as they do not produce the enzymes needed to break down the lactose contained in dairy.

If a cat consumes dairy, it can result in diaarhoea and vomiting, flatulence or abdominal cramping, and upset.

Dairy contains high amounts of fat, which can lead to obesity in cats as well. [6,7]


According to the ASPCA and Pet Poison Helpline, avocados are poisonous for cats due to a toxin known as Persin. Persin is in an Avocado’s leaves, fruit, and seed.

Persin is toxic for cats because it causes fluid accumulation in the lungs (pulmonary edema). This fluid accumulates in the air sacs of the lungs, resulting in difficulty breathing. Symptoms of the condition also include coughing, weakness, rapid breathing, and a blue tongue or lips.

In large doses, Persin can be fatal. If your cat has a blue tongue or blue lips, take them to the nearest emergency veterinary center immediately. [8,9]


There is no firm evidence to suggest that grapes are 100% toxic for cats, but they are a toxic food for dogs where they can cause kidney failure and even death. 

Generally, it is best to avoid feeding your cat grapes as there is no conclusive evidence to suggest they’re safe. According to the ASPCA, Grapes are poisonous for pets.

Symptoms of grape poisoning include vomiting and diarrhea, abdominal pain, tremors, seizures, and a reduction in urination.

Please speak to your vet if you suspect your cat has ingested even a small number of grapes. [3,10,11]


Caffeine contains an alkaloid known as theobromine found in foods and drinks such as chocolate, tea (incl. Herbal tea and Green tea), and coffee. It is toxic in both cats and dogs.

Caffeine can cause cardiac arrhythmias and respiratory difficulties by raising a cat’s blood pressure, leading to tremors or seizures, and even death if consumed in a large quantity. [12]


At the present moment, based on scientific studies, it is not poisonous to feed your cat tuna; however, it is highly addictive for cats. In addition, tuna causes significant health issues in cats if they consume too much and contain toxic ingredients such as mercury.

A small amount of tuna every so often will not harm your cat. 

If consumed in large doses, tuna can cause mercury poisoning leading to loss of coordination, difficulty walking, and vitamin deficiencies. Tuna can also destroy a vitamin known as thiamine (Vitamin B1), which helps your body digest and turn food into energy for your nervous system.

If a cat lacks thiamine, it can lead to neurological problems such as loss of appetite, seizures, and even death. [13,14,15]


Like dogs, cats cannot consume chocolate due to toxins known as Methylazanthines (theobromine and caffeine), which is in cocoa beans. We discussed why caffeine is toxic for cats previously.

Theobromine affects a cat’s central nervous system as well as its respiratory system and cardiovascular system. Typical symptoms of chocolate poisoning in cats include; vomiting and diarrhea, weakness, seizures, rapid breathing, and increased reflex response.

Some chocolates, like dark chocolate, are higher cocoa, so they’re more toxic for cats. Milk chocolate is less harmful in comparison as it contains less cocoa. [3,16]


Raisins, similar to grapes, are toxic for cats. We have previously discussed why grapes are poisonous for cats, but the same information applies to raisins.

Symptoms can take several hours to develop; however, please speak to your vet immediately if you suspect they have consumed raisins. [3,10,11]

Fat Trimmings

Giving your cat fatty foods is a sure way of making them obese. In North America, approximately 30-35% of cats are considered obese. Furthermore, obesity is the most common preventable disease in cats.

This disease can lead to cats developing dangerous diseases such as cancer, heart disease, diabetes mellitus (DM), or hypertension. In addition, obesity increases the likeliness of a cat developing a life-threatening condition known as hepatic lipidosis. 

Hepatic lipidosis (a.k.a. Fatty liver syndrome) is one of the most common liver diseases discovered in cats. It is fatal if left untreated.

If you see evidence of yellow in the whites of a cat’s eyes, then contact a vet immediately. [17,18]

Raw Green Potatoes

Raw green potatoes are part of the same family as green tomatoes, the Solanaceae family. These vegetables contain a poisonous alkaloid known as Glycoalkaloid Solanine. We have previously discussed the dangers and toxicity of this alkaloid. [1,2]


Cooked bones are more dangerous than you think as they can contain bacteria such as E. coli and Salmonella. Both of these bacterias are harmful to humans as well as pets.

In addition, bones can splinter, perforating a cat’s intestines due to the sharp edges and lead to infection. If large chunks are consumed, it can lead to intestinal blockages and ultimately life-threatening conditions such as peritonitis. [19]

Raw Eggs

Eggs, when cooked, can be a great source of protein and fat in a diet. However, there are significant risks with feedings eggs (in general) to cats.

The egg yolk itself in scrambled eggs or boiled eggs is high in fact content, raising the chances of your cat becoming obese. Obesity can lead to a life-threatening condition known as Hepatic Lipidosis; we discussed the dangers of this condition.

Obesity increases the chances of your cat developing gastrointestinal (GI) upset and pancreatitis. 

In addition, raw egg is highly likely to become infected with bacteria such as Salmonella, which is highly infectious to humans and pets. It is estimated that around 1.35 million people, per year, in the United States are infected by Salmonella.

Adjusting your cat’s diet should always be done with the guidance of a veterinarian. [19,20]


According to the ASPCA, Chives are toxic for cats and part of the Allium family, the same as Onions. We previously the dangers of the Allium family and the toxic compounds sulfoxides and aliphatic sulfides. [3,4,5,21]

Dog Food

While dog food is not toxic to cats, it can cause serious health issues if consumed in large doses. 

Cats are obligate carnivores; they require a diet of protein and animal fats for their bodies to function correctly. Simply, a cat’s diet requires different nutritional needs than those of a dog. Cats need nutrients such as Vitamin A, Taurine, and arachidonic acid. 

Taurine is an amino acid vital for vision, digestion, muscle growth and functionality, and maintaining a healthy immune system. Unlike other animals, cats have a hampered ability to develop taurine naturally. So instead, they obtain this acid through their diet.

Unfortunately, if your cat develops low taurine levels, this can lead to a condition known as feline taurine retinopathy (blindness). If caught early, this condition can be stopped. In addition, a lack of taurine can cause dilated cardiomyopathy (DCM). This condition eventually leads to heart failure due to the heart being unable to pump sufficient blood around the body at the right pressure. [22,23,24,25]


According to the Pet Poison Helpline, rhubarb contains oxalic acid and soluble calcium oxalate crystals found in its leaves. 

Too much oxalate in the body can lead to hyperoxaluria, a condition that leads to surplus oxalates passing in the urine. Hyperoxaluria can cause an accumulation of oxalates in the organs, leading to kidney failure if left untreated.

Small levels of toxicity will lead to vomiting and diarrhea. However, large exposure to oxalate poisoning can cause typical symptoms such as; vomiting (incl. blood), abdominal pain, sore throat, and nausea. [3,27,28,29]


Consuming too much liver can result in vitamin A toxicity and develop into hypervitaminosis A. This condition primarily affects your cat’s bones.

Common symptoms of hypervitaminosis A include anorexia, neck stiffness, weight loss, constipation, and lameness. In severe cases, cats can develop deformed bones, bone growths, and osteoporosis.

Vitamin A toxicity can lead to death. [30,31]


Cats can eat bread; however, the issue is how much they can consume and whether it is safe.

Yeast rises, and the same applies when it’s ingested too, it expands in the stomach. In addition, yeast produces excessive amounts of Ethanol (we previously spoke about the danger of Ethanol when discussing Alcohol).

Finally, yeast can cause a life-threatening emergency, stomach bloating, and gastric torsion. This can lead to severe abdominal pain or difficulty breathing.

If you suspect your cat is suffering due to yeast consumption, speak to the vet immediately. [32]


Typically, you can find xylitol in gum, candy, mints, breath fresheners, and some brands of peanut butter. 

Please read the label carefully before giving any to your cat. While peanut butter is safe to consume if it doesn’t contain Xylitol, we would urge on the side of caution and avoid it together.

Xylitol causes an insulin release in our bodies, resulting in low blood sugar (also known as hypoglycemia). 

Common symptoms include; drowsiness, nausea, heart palpitations, pupil dilation, and tachypnea (rapid breathing). Inevitably, if left untreated, it can lead to kidney failure and even death. [33


According to the ASPCA, cherries are toxic for cats due to a chemical called Amygdalin. Its typically found in fruits such as apricots, almonds, apples, and peaches; however, in cherries, its pits, stems, and leaves are the parts that contain amygdalin.

Amygdalin is converted into cyanide by the body, which in large quantities is lethal. Cyanide stops blood cells from utilizing oxygen, leading to respiratory or cardiac failure, tremors, incoordination, and even death.

Clinical symptoms of cyanide poisoning include; bright red gums, dilated pupils, or laboured breathing. 

There is limited scientific evidence that suggests the fruit’s body is toxic for cats. However, be sure to remove the pits, stems, and leaves to be sure. [34,35]


Persimmons such as plumbs or peaches are not toxic to cats; it is the seeds in them that are primarily dangerous for them. In addition, persimmons contain laxatives which can lead to complications for your cat.

Primarily, the seeds are dangerous for cats as they can cause significant problems for their small intestines, even blocking them. [3]

Salt or Salty Foods

In moderation, salt is not a bad thing to have in any diet as it’s essential for normal bodily functions. However, salt can lead to excessive thirst and urination, dehydration, or even ion poisoning in large doses.

Common signs of salt poisoning include; weakness, diarrhea, muscle tremors, and seizures. 

If you suspect your cat has salt poisoning, try to give your cat plenty of water to drink until you can get them to a vet.

It is highly dangerous to use salt to induce vomiting. Take your cat to a vet instead. [36,37]

Star Fruit (a.k.a Carambola)

Carambola is another fruit that contains oxalates and caramboxin. We previously discussed oxalates and the dangers they present when talking about Rhubarb.

Caramboxin is a neurotoxin that causes adverse neurological effects, including kidney disease, seizures, and even death [38,39,40]

Caraway Seeds

According to the ASPCA, Caraway seeds are toxic for both cats and dogs as they contain a high amount of monoterpene compounds. These are known as carvone and limonene.

Carvone (a terpenoid) has toxic qualities that can cause blood thinning. Limonene is a terpene that can cause severe skin and respiratory irritation.

The essential oils contained in caraways and these monoterpenes can cause vomiting and diarrhea, mild intestinal upset, blood thinning, or decreased glucose levels. [41]


Chamomile is not toxic to cats in small doses. It contains anthemic acid, tannic acid, bisabolol, and chamazulene.

This natural herb has been used for years due to its relaxing qualities. However, in large doses, it can be deadly. Common signs of chamomile poisoning can vary depending on each cat. However, typical symptoms include; hypersalivation, depression, vomiting, dermatitis, or allergic reactions.

If you believe your cat is suffering from any of the above symptoms, contact a vet immediately.

Final Thoughts

We hope this list has given you a good idea about what food not to feed cats. If you are ever worried about a particular food, seek veterinary advice to be sure.

Always be aware when browsing the internet to find information that anyone can write anything. Having the correct information about your cat’s diet is vital to have them happy and healthy.

Check out our latest article on wet vs dry food and which is best for your cat’s nutritional needs. 

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James Fuller and Mollie

James Fuller

Founder & Chief Content Creator

I’ve owned a pet most of my life. In fact, I currently have both a cat, Milo, and a Jack Russel, Mollie! I’m the founder of Honest Whiskers. And my mission is to deliver a reliable, trusted website that only uses evidence-based information.

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