Cats can be surprisingly curious about whatever is on your plate.
A little chicken disappears from the cutting board. A paw reaches toward your glass of milk. You open a can of tuna and suddenly your cat appears from another room as if summoned by magic.
Sharing a tiny bite may feel harmless, but cats have very different nutritional needs from humans—and some everyday foods can be genuinely dangerous.
There is also an important distinction worth making:
Not every food on this list is “poisonous” in the same way.
Some, such as chocolate, onions, and alcohol, can cause true toxicity. Others, such as milk, dog food, or canned tuna, may cause digestive problems or nutritional deficiencies when fed regularly.
Either way, they're foods that shouldn't become part of your cat's normal diet.
Here are 20 foods every cat parent should know about.
1. Chocolate
Chocolate is dangerous for cats just as it is for dogs.
It contains theobromine and caffeine, compounds known as methylxanthines. Cats don't process these substances the way humans do, and enough chocolate can affect the nervous system and heart.
Possible symptoms include vomiting, diarrhea, restlessness, abnormal heart rhythms, tremors, and seizures.
Dark chocolate, baking chocolate, and cocoa powder contain higher concentrations of these compounds than milk chocolate, making them particularly concerning.
Fortunately, cats aren't usually as interested in sweets as dogs are.
That doesn't mean chocolate should ever be left where a curious cat can investigate it.
2. Coffee and Other Sources of Caffeine
Your cat doesn't need help waking up in the morning.
Coffee, tea, energy drinks, caffeine supplements, coffee grounds, and other caffeinated products should all be kept away from cats.
Caffeine stimulates the central nervous system and can cause vomiting, hyperactivity, an elevated heart rate, tremors, and seizures.
Cornell specifically lists caffeine as toxic to both dogs and cats.
Used coffee grounds can be particularly easy to forget about, so make sure trash and compost containers aren't accessible.
3. Alcohol
A cat probably isn't going to order a cocktail.
But alcohol exposure can happen more easily than you might think.
Alcohol may be found in:
- Beer, wine, and liquor
- Mixed drinks
- Alcohol-containing desserts
- Fermenting foods
- Some household products
Ethanol acts as a central nervous system depressant and can cause vomiting, poor coordination, weakness, difficulty breathing, coma, and, in severe cases, death.
All animal species can be affected by alcohol poisoning.
Don't leave unfinished drinks somewhere your cat can reach them.
4. Onions, Garlic, Chives, and Leeks
These foods all belong to the Allium family.
And cats are particularly sensitive to them.
Allium compounds can damage red blood cells and lead to hemolytic anemia. The risk applies whether the ingredients are raw, cooked, dried, powdered, or incorporated into another food.
That makes onion powder and garlic powder especially easy to overlook.
Soup, sauces, seasoning blends, baby foods, gravies, and prepared meats can all contain them.
Possible signs may not appear immediately and can include weakness, pale gums, reduced appetite, lethargy, and collapse.
So even if the meat on your plate appears safe, always consider how it was seasoned.
5. Grapes
Grapes are well known for causing serious kidney problems in dogs.
The evidence surrounding cats is less extensive, largely because cats are less likely to eat large quantities of grapes in the first place.
However, veterinary poison-control resources, including Cornell's feline safety guidance, still list grapes among foods that should be kept away from cats.
There's no nutritional reason for your cat to eat them anyway.
The safest approach is simply to keep grapes off the menu.
6. Raisins
Raisins are dried grapes, so the same precaution applies.
They're also easier to overlook because they often appear inside other foods, including:
- Trail mix
- Bread
- Cookies
- Granola
- Cereals
- Baked desserts
Keep those foods where your cat can't reach them. Cornell includes raisins among common feline food hazards as well.
7. Foods Containing Xylitol
Xylitol is a sugar substitute commonly found in some sugar-free products.
You may encounter it in certain gums, candies, baked goods, toothpaste, mouthwash, and other products.
The dramatic hypoglycemia and liver toxicity associated with xylitol are best established in dogs, and feline-specific data are much more limited.
Still, veterinary and FDA safety resources recommend keeping xylitol-containing products away from pets, and there is no benefit to intentionally giving them to cats.
Check ingredient labels before sharing anything labeled “sugar-free.”
8. Raw Yeast Dough
Raw bread dough containing yeast presents two separate dangers.
First, the warm environment inside the stomach allows the dough to continue expanding.
That can cause severe stomach distention.
Second, fermenting yeast produces ethanol, meaning the animal can effectively develop alcohol poisoning from inside the digestive system.
Raw yeast dough can therefore cause abdominal swelling, weakness, disorientation, low body temperature, seizures, and other serious complications.
If you bake at home, never leave rising dough where a cat can get into it.
9. Raw Meat
Cats are carnivores.
That doesn't automatically mean raw supermarket meat is the safest way to feed them.
Raw meat can contain pathogens such as Salmonella and other disease-causing organisms that pose risks both to cats and to people in the household. Raw diets can also become nutritionally unbalanced when they aren't carefully formulated.
A cat's wild ancestors eating prey isn't the same thing as a house cat eating an improperly balanced bowl of raw grocery-store meat every day.
If you're interested in a homemade diet, it should ideally be developed with veterinary nutritional guidance.
10. Raw Eggs
Raw eggs come with similar concerns.
They may carry harmful bacteria, and raw egg whites contain avidin, a protein that can interfere with biotin availability when consumed in sufficient amounts over time.
A little properly cooked egg can be acceptable for many healthy cats.
Raw egg shouldn't be treated as a routine health food.
11. Raw Fish
Here's another food that sounds like it should naturally belong in a cat's bowl.
Not necessarily.
Some species of raw fish contain thiaminase, an enzyme that destroys thiamine, or vitamin B1.
A diet containing large amounts of thiaminase-rich raw fish can eventually contribute to thiamine deficiency, which may produce serious neurological problems.
Cooking destroys thiaminase.
Fish can certainly be part of properly formulated cat food.
That's very different from feeding raw fish as the primary diet.
12. Bones
You've probably seen cats in cartoons happily chewing on fish bones.
Real life is less cute.
Bones can splinter, become lodged in the throat, injure the mouth or digestive tract, or create an intestinal obstruction.
Veterinary guidance warns that both dogs and cats can suffer gastrointestinal injury or obstruction from swallowed bones.
Cooked bones can be particularly brittle.
The safest bone for your cat is generally the one they don't get to eat.
13. Milk and Dairy Products
The image of a cat drinking from a saucer of milk is everywhere.
The biology tells a different story.
Many adult cats don't produce enough lactase, the enzyme needed to properly digest lactose.
As a result, milk and other dairy products can lead to diarrhea, gas, or other digestive upset. Cornell specifically advises that milk isn't generally recommended as a cat treat.
Milk isn't poisonous in the way chocolate is.
It's simply unnecessary—and many cats don't tolerate it particularly well.
Fresh water is a much better everyday drink.
14. Human Canned Tuna as a Regular Meal
Open a can of tuna and there's a decent chance your cat will suddenly become your best friend.
A small amount occasionally is one thing.
Building your cat's diet around canned tuna made for people is another.
Human canned fish isn't formulated to provide all of the nutrients cats require. Cornell notes that cats fed canned fish products intended for humans have even developed potentially serious neurological disorders.
So tuna should not replace a complete and balanced cat food.
Your cat may strongly disagree with this policy.
Fortunately, they're not responsible for nutritional planning.
15. Dog Food as a Regular Diet
If you live with both cats and dogs, you may occasionally catch your cat stealing from the dog's bowl.
A few bites aren't usually the emergency.
The problem is feeding dog food as the cat's regular diet.
Cats have nutritional requirements that dogs do not. They need dietary sources of nutrients such as taurine, vitamin A, arachidonic acid, and higher levels of certain amino acids.
A diet formulated for dogs cannot reliably meet those long-term requirements.
Dogs and cats may share a home.
They shouldn't automatically share the same diet.
16. Too Much Liver
Liver is nutrient-rich and isn't inherently forbidden.
The problem is too much of it over a long period of time.
Liver contains very high levels of vitamin A.
Cats repeatedly fed diets containing excessive amounts of liver can develop vitamin A toxicity, which may lead to abnormal bone growth, stiffness, neck pain, and difficulty moving.
Some of these skeletal changes may be permanent.
So liver isn't something that needs to be feared.
It simply shouldn't become the foundation of an unbalanced homemade diet.
17. Fatty Table Scraps
Fatty meat trimmings, fried foods, butter-heavy leftovers, and greasy scraps aren't good everyday treats for cats.
High-fat foods can cause gastrointestinal upset, and veterinary poison-control guidance warns that fatty foods can contribute to problems such as vomiting, diarrhea, and pancreatitis in pets.
Cats also need surprisingly few calories compared with humans.
A “tiny” piece of rich human food may represent much more of their daily calorie intake than you think.
18. Excessively Salty Foods
A small amount of sodium is an essential part of a balanced diet.
That doesn't mean your cat should be eating salty human snacks.
Foods such as chips, highly salted meat, salty sauces, and heavily seasoned leftovers can deliver far more sodium than a cat needs.
Excessive salt intake can cause increased thirst and urination and, at sufficiently high amounts, more serious neurological and electrolyte problems.
Your cat doesn't need a potato chip.
Even if they insist otherwise.
19. Green Tomatoes and Tomato Plants
Here's another area where internet lists often oversimplify things.
A ripe red tomato itself is generally considered non-toxic.
The bigger concern is the tomato plant and unripe green fruit.
ASPCA lists tomato plants as toxic to both dogs and cats and notes that exposure can cause gastrointestinal upset, weakness, lethargy, and other symptoms.
As the tomato ripens, levels of the problematic compounds decrease significantly.
So there's no need to panic if your cat licks a piece of ripe tomato.
But don't let them chew on tomato plants or unripe fruit.
20. Raw or Green Potatoes
Potatoes are another food where preparation matters.
Cooked potato in a small amount isn't generally considered toxic.
Raw and especially green potatoes are more concerning because they contain higher concentrations of naturally occurring glycoalkaloids associated with gastrointestinal problems.
ASPCA recommends avoiding raw potatoes while noting that properly cooked potato can be offered in moderation.
Again, there's not much reason for potatoes to be part of a cat's diet in the first place.
What Should Your Cat Eat Instead?
Cats are obligate carnivores, meaning their nutritional requirements differ significantly from ours.
The easiest option for most households is a commercial food labeled as complete and balanced for the cat's appropriate life stage.
That helps ensure your cat receives the necessary amounts and proportions of protein, amino acids, fats, vitamins, and minerals.
Treats are fine in moderation, but Cornell recommends keeping treats to a relatively small portion of overall calorie intake rather than allowing snacks and table food to replace nutritionally complete meals.
Your cat doesn't need your dinner to feel included.
They mostly need food designed for them.
What If Your Cat Eats Something They Shouldn’t?
Don't wait for obvious symptoms if you know your cat has swallowed something potentially toxic.
Try to determine:
- What they ate
- Approximately how much
- When they ate it
- The product or ingredient list, if available
Then contact your veterinarian or an animal poison-control service.
Don't try to make a cat vomit at home unless a veterinarian specifically instructs you to do so. Some home methods can cause additional injury.
Cornell advises contacting a veterinarian or poison-control service promptly when poisoning is suspected.
Cats Don’t Always Know What’s Safe
Cats can be surprisingly selective eaters.
They can also occasionally make terrible decisions.
They don't understand that the sauce on your dinner contains garlic, that a cup contains caffeine, or that the dough on the counter is still fermenting.
That's our job.
Keep genuinely toxic foods safely stored, avoid making human leftovers part of your cat's regular diet, and choose treats specifically suited to feline nutritional needs.
Because the safest meal for your cat usually isn't whatever happens to be on your plate.
It's the one that was actually made for them.