Several common foods and plants can seriously harm or kill cats, and some — like lilies — are dangerous even in tiny amounts. If your cat has eaten something from this list, contact your veterinarian or the ASPCA Animal Poison Control Center (888-426-4435) immediately. Don't wait for symptoms to appear.
Why Cats Are Especially Vulnerable to Food Toxins
Cats have a unique metabolism that makes them more sensitive to certain compounds than dogs or humans. Their livers lack some of the enzymes needed to break down specific chemicals, which means substances that pass through other animals safely can build up to dangerous levels in a cat's body.
Cats are also obligate carnivores, meaning their digestive systems evolved to process animal protein — not the wide variety of foods that omnivores handle. That biology is part of why so many everyday human foods land on the toxic list.
Lilies: The Most Dangerous Plant for Cats
True lilies — including Easter lilies, tiger lilies, daylilies, and Asiatic lilies — are severely toxic to cats. Every part of the plant is dangerous: the flowers, leaves, pollen, and even the water in a vase containing cut lilies. Ingesting even a small amount can cause acute kidney failure within 24 to 72 hours.
If you see your cat chew on a lily or notice pollen on their fur (which they may groom off and ingest), treat it as an emergency. This is not a wait-and-see situation. Get to a vet immediately.
Peace lilies and calla lilies are a separate concern — they're not true lilies and don't cause kidney failure, but they contain compounds that irritate the mouth and gastrointestinal tract.
Alliums: Onions, Garlic, Chives, and Leeks
The entire allium family is toxic to cats. This includes onions, garlic, chives, leeks, shallots, and scallions — raw, cooked, dried, or powdered. Garlic powder is particularly concentrated and therefore particularly dangerous.
These foods damage red blood cells, leading to a condition called hemolytic anemia. Symptoms may be delayed and include weakness, lethargy, reduced appetite, pale or yellowish gums, and rapid breathing. Even small repeated exposures can accumulate into a serious problem, so this isn't just about large one-time doses.
Be especially cautious with human foods like soups, sauces, baby food (which sometimes contains onion powder), and broths before sharing anything with your cat.
Grapes and Raisins
Grapes and raisins are known to cause kidney failure in cats, though the exact toxic compound hasn't been definitively identified. Because the mechanism isn't fully understood, there's no established "safe" amount — any exposure should be treated as potentially serious.
Avoid letting cats access grapes, raisins, or foods that contain them, including fruit cakes, trail mix, or certain baked goods.
Xylitol
Xylitol is an artificial sweetener found in sugar-free gum, certain peanut butters, candies, baked goods, and some medications and toothpastes. It's extremely toxic to dogs, and while the research on cats is less extensive, it should be considered dangerous and avoided entirely.
Check labels carefully on anything sugar-free before it comes anywhere near your cat.
Alcohol
Cats are far more sensitive to alcohol than humans. Even small amounts of beer, wine, spirits, or foods cooked with alcohol can cause serious problems including vomiting, disorientation, breathing difficulties, and dangerous drops in blood sugar and body temperature. There is no safe amount of alcohol for cats.
Caffeine
Coffee, tea, energy drinks, soda, some medications, and even chocolate contain caffeine, which is toxic to cats. Signs of caffeine poisoning include rapid breathing, restlessness, muscle tremors, and heart palpitations. Keep all caffeinated drinks out of reach, including that morning coffee left on the counter.
Chocolate
Chocolate contains both caffeine and theobromine, a compound cats cannot metabolize effectively. Dark chocolate and baking chocolate are the most dangerous due to higher concentrations, but milk chocolate and white chocolate are not safe either. Symptoms can include vomiting, diarrhea, increased thirst, restlessness, and more serious cardiac effects.
Cats are generally less drawn to sweet tastes than dogs (they lack sweet taste receptors), but some cats are curious enough to investigate — especially if chocolate is mixed into something else.
Raw Dough and Yeast
Unbaked bread dough that contains yeast can expand in a cat's warm stomach, causing painful bloating. As the yeast ferments, it also produces alcohol, creating a secondary toxicity risk. Keep your cat out of the kitchen when baking with yeast.
Raw Eggs
Raw eggs carry the risk of Salmonella and E. coli contamination. They also contain avidin, a protein that interferes with the absorption of biotin (a B vitamin), which can cause skin and coat problems with prolonged exposure. Cooked egg is generally considered safe for cats in moderation — it's the raw form that raises concern.
Certain Fish in Excess: Raw and Canned Tuna
This one is nuanced. Small amounts of cooked fish aren't inherently toxic to cats, but a few fish-related issues are worth knowing:
- Raw fish contains thiaminase, an enzyme that breaks down thiamine (vitamin B1). Regular raw fish consumption can lead to a thiamine deficiency, which affects the nervous system.
- Canned tuna for humans, fed too frequently, can contribute to mercury buildup and nutritional imbalances. It's also so palatable that some cats will refuse anything else — a problem for balanced nutrition.
Fish-flavored cat food formulated for cats is a different story — those products are balanced and safe for regular feeding.
Macadamia Nuts
Macadamia nuts are well-established as toxic to dogs and are best avoided for cats as well. The toxic mechanism in cats isn't thoroughly studied, but the potential risk makes keeping these nuts away from pets the sensible approach.
Dairy: A Common Misconception
Despite the cultural image of cats lapping up milk, most adult cats are lactose intolerant. Their digestive systems don't produce enough lactase to break down lactose properly, which can lead to diarrhea, bloating, and stomach upset. Dairy isn't toxic the way lilies or onions are, but it's worth knowing that "a little milk as a treat" often causes more discomfort than pleasure.
Other Foods to Avoid
- Nutmeg — toxic to cats in more than trace amounts, can affect the nervous system
- Green tomatoes and tomato leaves — contain solanine, which is harmful to cats (ripe tomato flesh in small amounts is generally considered low risk)
- Raw potatoes and potato plants — also contain solanine
- Avocado — the fruit, pit, skin, and leaves contain persin, which can cause digestive distress
- Mustard seeds — can irritate the digestive tract and cause more serious issues in larger amounts
- Dog food (as a primary diet) — not acutely toxic, but formulated differently; long-term feeding can lead to nutritional deficiencies specific to cats, including taurine deficiency
How Tracking What Your Cat Eats Can Help
One challenge with food toxicity is that small repeated exposures — a bit of garlic here, a lick of sauce there — can accumulate without obvious immediate symptoms. Keeping a consistent record of what your cat eats makes it easier to spot patterns, flag potential exposures, and give your vet accurate information if something goes wrong. The Pet AI Nutrition Tracker app lets you log your cat's daily meals and flag ingredients so nothing slips through unnoticed — which is especially useful in multi-person households where one person may not know what another has given the cat.
What to Do If Your Cat Eats Something Toxic
Act quickly. Don't wait for symptoms — some toxins cause irreversible damage before clinical signs appear.
- Remove your cat from the source of the toxin.
- Note what they ate and roughly how much.
- Call your vet or the ASPCA Animal Poison Control Center: 888-426-4435 (a consultation fee may apply).
- Do not induce vomiting unless a professional specifically tells you to — it can make some situations worse.
Having a list of what's in your home — and what your cat has access to — ready to share with your vet can save critical time in an emergency.