Foods that are toxic to cats
Cat food commercials hinge on the idea that cats are finicky eaters. But most of the cats in my life have enjoyed vigorous appetites. They’ve always been curious about the foods I’m eating and sometimes want to try a bite, too.
But is it safe to give your cat a bite of human food?
Not always. Just because a food is safe or even healthful for you to eat, doesn’t mean it’s safe or healthful for your cat. In fact, many people foods are poisonous to cats.
Before we go any further, here is the contact information for two reputable poison-control hotlines. Keep these numbers somewhere you can find them right away because time may be of the essence when your cat has ingested something toxic. Taking quick action can literally be the difference between life and death if your cat has eaten something he shouldn’t have.
ASPCA Animal Poison Control Center: (888) 426-4435
Pet Poison Helpline: (855) 764-7661
While you’re dialing the number, try to determine how much of the toxic food your cat has eaten. Quantity matters for certain poisons.
But remember that the best medicine is prevention. Keep all of the foods mentioned in this post out of the reach of curious cats.
What symptoms should I watch for if I think my cat has eaten something toxic?
Unfortunately, poisoning looks like a lot of other illnesses and symptoms can be wide-ranging. Here are a few signs and symptoms your cat might display if she’s eaten toxic human food. The only way you’ll know for sure they’re due to poisoning is if there is some evidence your cat has been eating something dangerous.
Many of these symptoms are very serious and indicate that your cat needs immediate veterinary attention. Even if you’re unsure if your cat is displaying a symptom due to poisoning, contact your veterinarian immediately.
|Muscle tremors or rigidity
|Loss of movement control
Foods you should never feed your cat
Some foods that humans eat every day, foods that are even healthful for people to eat, can be dangerous for cats to eat. Following is a list of the foods that you should never allow your cat to eat:
Onions, garlic, and other Alliums
Onions, garlic, shallots, scallions, chives, and leeks are all part of the genus Allium. There are actually hundreds of Allium species but these are the ones most likely to be found on the dinner table.
Alliums contain sulfur in the form of organosulfur compounds, and these compounds are what make them so healthful for people to eat. Alliums are credited with having antioxidant, antibacterial, immune-boosting, and anti-inflammatory properties.
These very same sulfur compounds, however, will cause a cat’s red blood cells to become fragile and burst. Destruction of red bloods cells can lead to anemia, including hemolytic anemia (in which red blood cells are destroyed faster than the body can make them), Heinz body anemia (where the membrane of the red blood cells become distorted) , and methemoglobinemia (in which the iron in hemoglobin – the molecule that carries oxygen from the lungs to the body – becomes damaged).
It takes only a small amount of onions or garlic to harm a pet, but cats are far more sensitive to Alliums than dogs. Onion poisoning can happen from ingesting a larger amount of onions all at once, or a cat can be poisoned slowly, by eating small amounts, a little at a time.
Concentrated versions of garlic and onions are especially dangerous. Garlic powder and onion soup, for example, are even more toxic than their fresh versions.
Have you ever given a sick cat baby food? Or a cat who won’t drink, a little bit of chicken broth? Did you know that some baby foods and meat broths contain onion and garlic for flavoring? Many “innocent” foods that might be otherwise safe for cats could contain onion and garlic – be sure to read labels.
Other people foods, such as tomato sauce, pizza, seasoned rice, crackers, pot pies, may also be flavored with onion and garlic. Your cat shouldn’t be eating any of these foods either, but you should be aware of the risk if your cat helps himself to a bite of something on your plate.
A cat who has been poisoned by onions or garlic may display lethargy, weakness, a reduced appetite, pale gums, and urine that is orange or red in color. If you think your cat has eaten onions or garlic, for example, take him to your veterinarian immediately – there are actions a vet can take to save your cat’s life.
Grapes and raisins
Grapes, and their dried versions: raisins, sultanas, and currants, are all poisonous to cats.
Oddly, we don’t know why these foods are toxic. It could be that cats can’t metabolize the pesticides that are on grape skins, or the tannins that are naturally part of the fruit.
Actually, that’s not entirely true. We know that grapes and raisins are toxic for dogs, but there is only anecdotal evidence that they're not safe for cats. It could be that cats just aren’t interested in grapes and raisins and so not enough cats have actually eaten them to collect data. Err on the side of assuming that grapes and raisins are deadly.
Grape toxicity does not seem to be dose-dependent. That means that ingesting a small amount of grapes is not necessarily “better” than ingesting a large amount. Even a small amount can lead to kidney failure. A cat may become hyperactive initially, but within 12 hours he may start vomiting. By 24 hours lethargy sets in, as does diarrhea, reduced appetite, abdominal pain, and decreased urination.
Grapes come in many forms. Grape juice is obviously dangerous, but you might forget that wine comes from grapes, too! Wipe up any spills immediately. There are often raisins in trail mix and cookies, and most definitely in raisin bread. Did you know that many granola and protein-type snack bars contain raisin paste or raisin juice, too? Just because you can’t see a raisin, doesn’t mean a product doesn’t contain them. 
If you have a habit of leaving a gorgeous bowl of grapes on the counter for snacking, it might just be time to slip that bowl into the fridge.
(If you're interested in keep your cats off the kitchen counter, read this post, "How to keep cats off the counter.")
The ethanol in an alcoholic beverage is rapidly absorbed in a cat’s gastrointestinal tract, metabolized by the liver, and quickly reaches the brain, just like it does in humans. But it takes far less alcohol to do serious damage to a cat’s body than to a person’s. Just two teaspoons of whiskey can induce a coma in a five-pound cat. A third teaspoon could kill her.
We already know that wine is dangerous for cats (see “Grapes” above), but so is beer and any kind of liquor. The higher the proof, the worse the symptoms.
Cats respond to alcohol in many of the same ways that we do: after a short initial period of excitement, other symptoms, such as depression, disorientation, confusion, increased thirst and urination, loss of movement control, lethargy, drooling, vomiting, and sedation sets in. But alcohol poisoning in cats can quickly result in more severe symptoms, including muscle tremors, a dangerously slow breathing rate, seizures, paralysis, coma, and death.
Alcohol can sneak into a wide range of household products including paint and varnish, medication, perfume, mouthwash, and antifreeze. Know what you have around the house and be careful about what is accessible to your cat.
Caffeine, which is present in so many of our foods, drinks, and medications, is harmful to cats. In large quantities, caffeine can prove fatal for cats, and there is, unfortunately, no antidote to save their lives if they accidentally ingest too much.
Caffeine is a stimulant – you already knew that and it’s probably why you drink coffee. It’s the stimulant nature of caffeine that is so dangerous to cats: it raises their blood pressure, causes cardiac arrhythmias, makes them lose muscle control, and experience tremors. Cats on caffeine can run a fever and become weak. In the worst cases, they may fall into a coma and die.
The first signs show up about 30 minutes after a cat ingests a caffeine-containing product. He may become hyperactive or restless. He may pace or meow excessively. This will continue for as long as 12 unhappy hours for the cat.
The key to saving a cat’s life is early intervention. Call your veterinarian as soon as you realize your cat has consumed something that contains caffeine. Consider not just coffee and tea, but cocoa, chocolate, cola, energy drinks, certain cold medications, painkillers, and diet pills. Your veterinarian has a few tools in his toolbelt, which can head off more severe caffeine poisoning, including inducing vomiting to prevent more of the caffeine from making its way into your cat’s bloodstream, administering activated charcoal to absorb caffeine in the stomach, and administering IV fluids to prevent dehydration.
While it’s unlikely that your cat will help himself to old coffee grounds, it’s better to dispose of them safely and immediately. Don’t leave tea bags lying around, and consider taking those oh-so-convenient single-serve coffee pods off the counter and putting them somewhere less convenient.
Chocolate can be lethal. It contains methylxanthines, including two specific compounds: caffeine and theobromine, that are highly poisonous to cats.
Fortunately, most cats won’t eat chocolate on their own.
The amount of caffeine and theobromine in the chocolate matters. The more cocoa in a product, the more caffeine and theobromine. White chocolate, while still dangerous, has less cocoa, while dark chocolate and unsweetened baking chocolate has the most and is the most dangerous. Even tiny amounts of dark or baking chocolate are dangerous.
A cat may begin to show signs of chocolate poisoning 6-12 hours after consuming it and the effects can last for up to three days in bad cases. A cat may vomit, have diarrhea, be restless, pant, have increased thirst and urination, experience muscle tremors, and weakness. Symptoms can progress to an abnormal heart rhythm, seizures, a drop in blood pressure, high fevers, coma, and death.
Raw eggs are not good for cats, nor for anyone else for that matter. Eating raw eggs raises the risk of food poisoning from bacteria like salmonella or E. coli.
But cats run a second risk from consuming raw eggs. Raw egg whites contain a glycoprotein called avidin. This protein binds to biotin, also called vitamin H, preventing the biotin from being absorbed by the body. 
Cats need biotin for a healthy coat, skin, and claws. It also helps carnivores, like cats, process the protein that they eat. Biotin also supports the thyroid and adrenal glands, reproductive and nervous systems.
This doesn’t mean that you can’t serve your cat cooked eggs. Cooked eggs are a great source of protein and vitamins. But check with your veterinarian first as some cats are allergic to eggs. If you decide to try feeding your cat eggs, start with a tiny amount and watch for signs of allergy, which include vomiting, diarrhea, skin infections, and itchiness.
Raw meat and fish
Consuming raw meat and fish carries many of the same risks as consuming raw eggs. The bacteria in uncooked meats and fish can cause severe, even deadly food poisoning. Parasites are a risk, too, including roundworms, tapeworms, and Toxoplasma gondii. Ewww!
But raw fish adds one more risk for cats, which makes it especially dangerous. There’s an enzyme in raw fish called thiaminase that destroys thiamine, an essential B vitamin. Lack of thiamine can cause serious neurological problems and lead to convulsions and even coma. Cooking fish alters the thiaminase enzymes so they are no longer dangerous to cats.
A small amount of liver is safe for cats. It’s even a good source of protein, iron, and other nutrients.
But too much liver can cause vitamin A toxicity, also called hypervitaminosis.
Vitamin A is essential for cats (for us, and for dogs, too). Without enough vitamin A, a cat could go blind, among other things. But there is such a thing as too much of a good thing. And too much liver could result in a cat developing vitamin A toxicity.
The problem is that cats vary in how susceptible they are to vitamin A toxicity. Some cats never have any problems with it, while others seem more prone to the condition. There’s no established “safe” amount to give a cat, since sensitivity is so individual.
The other problem is that it takes a long time for the toxicity to develop. Most cats don’t show signs of vitamin A toxicity until they are middle-aged or older. By that time, they develop a kind of arthritis in which new bone grows at the joints, leading to stiffness or even fusing of the joints. This extra bone commonly forms in vertebrae at the neck, and cats become unable to groom themselves because it hurts to move. It may hurt to eat and to be picked up and held, too.
Vitamin A toxicity also affects other body systems, including liver problems and paralysis.
If a cat has an acute episode of overdosing on vitamin A (such as a cat who consumes a bottle of vitamin pills) there are steps a veterinarian can take to help prevent or reduce absorption. But once vitamin A toxicity sets in, there is little that can be done. The vitamin remains stored in a cat’s liver, likely for his lifetime.
Never feed your cat bread dough made with yeast, including sourdough bread dough, which contains wild yeasts.
The food itself isn’t toxic to start, but can become toxic in a cat’s stomach. As the yeast feeds on the sugar within the dough (in the nice, warm “proofing box” that is your cat’s belly), it produces carbon dioxide and alcohol in a process called fermentation. Alcohol (see above) is very toxic to cats. A cat can actually suffer from alcohol poisoning from consuming bread dough.
The carbon dioxide produced during fermentation can also be problematic. The same mechanism that causes bread dough to rise, can cause the dough to swell in a cat’s belly, leading to a twisted stomach called gastric-dilitation volvulus (GDV), or a bowel obstruction.
You’ll know you cat is suffering from GDV or an obstruction after consuming bread dough if she is vomiting, retching but not vomiting, has a distended stomach, and appears (or sounds) distressed.
Xylitol is a natural sweetener often used as a sugar substitute in chewing gum, toothpaste, baking products, breath fresheners, nasal sprays, candy, and mints, among other food, drug, and personal-care products.
We know that xylitol is very toxic to dogs. But we didn’t know if it was toxic to cats because the two major poison-control hotlines had never received any reports of a cat actually ingesting a xylitol-containing product. (Smart cats!)
There was a very small study conducted on six healthy cats that showed that xylitol doesn’t produce the same toxic effects in felines as it does in dogs. But I’d hardly say that six cats answers the question definitively.
In the absence of better data, I’d encourage you to keep xylitol-containing products out of paws reach. And if, by some chance your cat manages to ingest something with xylitol in it, call poison control.
Macadamia nuts are moderately poisonous to dogs, but it is unknown if they are also poisonous to cats.
These nuts contain an unknown toxin which can affect a dog’s digestive and nervous systems, causing vomiting, fever, muscle tremors, and depression.
Fortunately, macadamia-nut poisoning is usually non-fatal in dogs with supportive veterinary care like IV fluids and anti-fever medications.
But in the absence of any hard data about the safety of these nuts in cats, they are probably best avoided.
Salt is necessary for sustaining life. Fortunately, cats get all the salt they need from the meat they eat. Too much salt can cause salt poisoning.
Electrolytes are electrically charged essential minerals that help produce energy, enable muscle contractions (including those in the heart), and regulate the fluid levels in the blood, among other things, and too much salt can throw off the balance of electrolytes in a cat’s body. Severe salt-poisoning cases can even lead to death.
Cats can accidentally get salt poisoning in a variety of ways. An outdoor cat in winter may lick rock salt off his paws. An indoor cat may lap water from a saltwater aquarium, or consume homemade salt playdough.
Cats who have consumed too much salt will show signs within minutes, including lethargy, depression, excess salivation, vomiting, diarrhea, extreme thirst and urination, increased heart rate and respiratory rate, muscle cramps or tremors, seizures, and comas. Salt poisoning can also lead to death.
If you suspect your cat has eaten something containing too much salt, seek veterinary care immediately.
It’s almost not worth mentioning that citrus fruits are toxic, as most cats positively recoil at the smell of citrus. You’d be hard-pressed to find a cat willing to actually eat an orange, lemon, lime, clementine, grapefruit, tangerine, mandarin, or satsuma, or drink citrus juice of any kind. Good.
The most dangerous part of any citrus for a cat is the peel, which contains the most essential oils of any part of the fruit. The essential oils in citrus can be irritating to a cat’s gastrointestinal system, causing vomiting, diarrhea, and drooling, and also skin irritation if the skin touches one of these fruits. If a cat were somehow able to consume enough citrus oil, it could theoretically cause liver damage and even death.
Keep in mind that not only fresh fruit contains these oils. Many liquid potpourri formulas contain essential oils that can be hazardous, so beware if you keep any of these products in your home.
(For more information about a related topic, read, "How much should I feed my cat?")
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Dawn LaFontaine is a lifelong animal lover who always seems to have a little pet hair in her keyboard. Her blog, Kitty Contemplations, helps cat guardians better understand and care for the special beings they share their lives and homes with. Her cat-products business, Cat in the Box, sells beautiful, well-made, and award-winning products that she designed to meet the biological needs of cats.
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