15 Human Foods That Are Poisonous & Toxic To Cats

When it comes to foods that are truly poisonous to cats, the list is thankfully quite short. However, some foods that are traditionally associated with cats can actually cause more harm than good: think of the proverbial saucer of milk.

In this article, we’ll uncover the most common foods poisonous to cats as well as products that may seem healthy but which might actually irritate your cat.

Let’s look first at the everyday ‘human’ foods that can be seriously toxic to our feline friends.

Foods Truly Poisonous To Cats

While very few foods are toxic to cats, some foods, like chocolate, are truly poisonous. If your cat has ingested one of these foods, make an emergency call to your vet clinic.

The following seven foodstuffs can be seriously toxic to cats if ingested and all necessitate an emergency call to your vet clinic.

1. Onions, Garlic, & Chives

All of these foods form part of the Allium plant family and contain sulphoxides, the component that gives them their uniquely strong odour and taste.

What Happens If Your Cat Eats Onions, Garlic, Or Chives?

In cats, when these sulfur-containing compounds are broken down by the body and absorbed into the bloodstream, they cause damage to red blood cells. In severe cases, the red blood cells will rupture and release damaged haemoglobin proteins called Heinz Bodies, which can in turn lead to anaemia and even kidney damage.

Cats are more sensitive to onion toxicosis than dogs and initial clinical signs can be very vague and non-specific. Initially an affected cat may develop vomiting and/or diarrhea accompanied by loss of appetite.

Anemia can start to develop as soon as 12 hours after eating the onion/garlic/chive substrate, but normally there is a delay of 2-5 days.

It is during this time that you may notice your cat becoming quite lethargic, depressed and disinterested in normal activities. Also remember that any member of this plant family can cause toxicity to your cat regardless of whether it is in powdered, cooked, raw, or dehydrated form.

2. Xylitol

This is an artificial sweetener used in many human foods and other products, including chewing gum, sweets, nut butters, bakery goods, diabetic foods and toothpaste.

What Happens If Your Cat Eats Xylitol?

When it is eaten by cats, xylitol can cause an abnormal increase in insulin release from the pancreas, which in turn leads to a decrease in overall blood sugar levels.

Early signs of a xylitol problem are lethargy, vomiting and loss of muscle coordination, but without rapid treatment this can progress to cause liver failure and seizures.

3. Chocolate

Some foods, like chocolate, are truly poisonous to cats.

Chocolate contains a compound called theobromine, which is part of the methylxanthine family of compounds.

What Happens If Your Cat Eats Chocolate?

If it is eaten by your cat it can rapidly cause stomach upset; hyperactivity; adversely impact the kidneys and the nervous system, as well as trigger an abnormal heart rhythm. In the worst-case scenario it can be fatal.

Dark chocolate, cocoa powder, cocoa butter, and cocoa beans are the most dangerous types of chocolate as they contain the highest levels of theobromine compared to milk or even white chocolate.

Sadly, dark chocolate is also the most likely type of chocolate to appeal to your cat, as it has a bitter taste.

4. Coffee Pods, Beans, Grounds & Caffeinated Energy Drinks

Caffeine is another member of the methylxanthine family of compounds.

What Happens If Your Cat Eats Coffee Or Another Caffeinated Drink?

In cats, caffeine ingestion affects the bowels, kidneys, nervous and cardiovascular systems and can be fatal if left untreated.

Another risk for cats is that caffeine tastes bitter, which makes it very appealing to cats. Be aware that caffeine is present in many energy drinks and colas. Additionally, the potentially lethal effect may be exponentially worsened if it is contained in cocoa and chocolate.

5. Alcohol

Alcohol should never be offered to any pet. They metabolise it similarly to us humans, but as it is dose dependent on the size of the animal, it can be rapidly fatal for cats.

What Happens If Your Cat Consumes Alcohol?

Alcohol can cause vomiting, diarrhoea, decreased coordination and a depressed central nervous system. If left untreated it can lead to breathing difficulties, tremors, change the pH of blood and induce coma or seizures, ultimately resulting in death.

Alcohol isn’t always obviously presented as a beverage either, as it can be contained in many ‘normal’ household items including raw yeast for baking bread and rotting/fermenting fruit.

During these unprecedented COVID times please also be especially aware of not leaving alcohol hand gels and rubs near where curious cats might try to investigate.

6. Grapes, Raisins, & Currants

Similar to the Allium plant family, grapes contain a compound as yet unidentified, which affects the kidneys and can lead to sudden renal failure.

What Happens If Your Cat Eats Grapes, Raisins, Or Currants?

Repeated vomiting and hyperactivity can be early signs of poisoning and an emergency trip to the vet is essential. Remember too that raisins and currants can be present in raisin bread and trail mix.

7. Mouldy Food

If food goes mouldy it can lead to the production of specific poisons called mycotoxins and aflatoxins.

What Happens If Your Cat Eats Mouldy Food?

Aflatoxins and mycotoxins cause different symptoms in cats, but if left untreated can be fatal. Specific care needs to be taken with blue cheese, fallen fruit, stale bread, and other decaying organic matter.

Foods To Be Handled With Care

While not necessarily toxic, some foods can irritate your cat if ingested. Avoid letting your cat consume any of these items.

Cats are really unique when it comes to choosing what food to eat. We consider them to be highly fussy and often picky, but the reality may be simply due to the way that they perceive different substances.

Cats don’t actually have many taste buds when compared to either people or dogs and as mentioned earlier, they don’t have a high ability to taste sweet flavours. So rather than down to taste alone, when it comes to food choices cats are highly driven by smell, mouth feel, texture, shape, and temperature.

1. Milk & Dairy

Thinking back to our saucer of milk and eagerly lapping cat, it may seem very strange that this could be potentially harmful to our feline friends. However, most cats lack, or only have small amounts of, the enzyme lactase.

This enzyme is necessary to break down the lactose component of milk and other dairy products and without it, many cats can experience stomach upset with diarrhoea after eagerly lapping up some milk

2. Raw Meat, Fish & Eggs

Raw meat, fish and eggs can all contain potentially harmful bacteria such as E. coli and Salmonella. In addition, raw eggs contain a specific enzyme (avidin) that can reduce the absorption of biotin, one of the B vitamins.

In the long term, this can lead to skin and coat problems. Raw fish also contains a different enzyme that destroys another B vitamin, thiamine. This is an essential vitamin for cats and deficiency can result in serious neurological disorders, ultimately leading to convulsions and coma.

3. Liver

Liver is generally a great source of nutrients and very rich in Vitamin A. However, this is a fat-soluble vitamin, which means that it gets stored in the body. Over time excess vitamin A can lead to a serious toxicity called hypervitaminosis A, which leads to bone deformity and even fusion of elements of the spine.

4. Tuna

The type of tuna you give your cat determines whether or not it’s a good choice. Cats should eat unseasoned tuna packed in water.

Cats love tuna! In the short term, canned tuna packed in water is a great treat to give, but it’s not a long-term food as it causes malnutrition. It doesn’t have the specific nutrients that cats require for general health and over time it can also lead to mercury poisoning.

5. Nuts

Walnuts, pecans, almonds, and in fact all nuts, contain high levels of fats and oils. This can lead to tummy upset such as vomiting and diarrhoea. If ingested long-term, the high fat content of nuts can potentially cause pancreatitis.

6. Bones

Plain raw chicken muscle meat, organs, and bones should make up a small percentage of your cat’s diet.

Cats are used to hunting for their food. In the wild, this means crunching on mice and small birds including their bones. However, giving cooked bones or even small raw bones to cats is not a good idea as they splinter very easily. This in turn can cause choking, blockages, and even tears within the digestive tract.

Final Thoughts

There are many delicious and nutritious foods available to us today to choose for diets as well as tempting items to consider feeding to our cats.

Sadly, many of the foods that we think our cats actively enjoy aren’t actually all that healthy for them. Aside from milk and dairy products, think of fat trimmings from the Sunday roast.

Even though our cats will likely devour them at high speed, the excess fat can easily lead to vomiting and diarrhoea as their little systems simply can’t handle it. Cats are also extremely curious. It is this wonderful character trait, above all else that we need to be aware of when it comes to accidental poisoning.

If you’re ever in any doubt about what your cat may have eaten, don’t ever hesitate to pick up the phone and call your local vet.