Most of the time, a cat who steals a bite from your plate is fine. But a handful of everyday foods are genuinely dangerous to cats — and cats are more sensitive to some of them than dogs or people, because their bodies process certain compounds differently. Knowing the short list of real hazards (and the longer list of “not toxic, but not good for them”) helps you relax about the harmless stuff and act fast on the things that matter.
This guide focuses on foods. If you want to check a specific item quickly, our food safety checker gives you a fast answer. And if you also live with a dog, the hazard list differs in important ways — see foods toxic to dogs.
The quick-reference table
| Food | Risk level | Why it’s a problem |
|---|---|---|
| Onions, garlic, chives, leeks | Very dangerous | Contain compounds that damage red blood cells and cause hemolytic anemia. Cats are especially sensitive — even cooked, dried, or powdered forms (like onion/garlic powder in soups, baby food, or sauces) can do harm. |
| Chocolate & caffeine | Toxic | Methylxanthines (theobromine, caffeine) affect the heart and nervous system. Dark and baking chocolate are worst; coffee, tea, and energy drinks count too. |
| Xylitol (birch sugar) | Toxic | A sugar substitute in gum, candy, and some peanut butters. Less studied in cats than dogs, but treated as a serious risk — avoid entirely. |
| Alcohol | Toxic | Even small amounts can cause dangerous drops in blood sugar, body temperature, and breathing. Includes raw dough and unbaked desserts. |
| Raw bread dough | Dangerous | Yeast ferments in the warm stomach, producing alcohol and expanding painfully. A double threat: bloating and alcohol poisoning. |
| Grapes & raisins | Use caution | Documented kidney injury in dogs; the picture is less clear in cats, but the safest call is to keep them away entirely. |
| Dog food | Not toxic, inadequate long-term | Won’t poison a cat, but lacks enough taurine, vitamin A, and protein. Long-term feeding can cause taurine deficiency (heart and eye disease). |
| Tuna (in excess) | Use caution | Fine as an occasional treat; as a staple it can crowd out balanced nutrition and, over time, contribute to deficiencies. |
| Milk & dairy | Not toxic | Most adult cats are lactose intolerant — dairy commonly causes diarrhea and stomach upset, not poisoning. |
| Raw fish | Use caution | Some raw fish contains thiaminase, an enzyme that destroys thiamine (vitamin B1); regular feeding can lead to deficiency. |
The truly dangerous ones
Onions, garlic, chives, and leeks top the list for cats. The whole Allium family contains organosulfur compounds that damage red blood cells, leading to a condition called hemolytic anemia. The ASPCA’s Animal Poison Control Center and Merck Veterinary Manual both flag cats as particularly vulnerable. What surprises many owners is that cooking doesn’t help — onion powder, garlic powder, and dehydrated flakes are if anything more concentrated. That’s why hidden sources matter: gravies, broths, baby food, and seasoned leftovers can all carry enough to cause trouble. Signs of anemia (weakness, pale gums, reddish urine, rapid breathing) may not appear for a few days, so don’t wait for symptoms if you know your cat ate an Allium.
Chocolate and caffeine contain methylxanthines, which cats clear slowly. Darker and more bitter products — baking chocolate, cocoa powder, espresso — pack the biggest punch, but coffee grounds, tea bags, and energy drinks all count. Watch for restlessness, a racing heart, vomiting, or tremors.
Xylitol (also labeled “birch sugar”) is a sweetener in sugar-free gum, mints, candy, and some peanut butters. Its dangers are best documented in dogs; in cats the research is thinner, but poison control resources advise treating it as a real hazard and keeping it out of reach entirely.
Alcohol and raw yeast dough belong together. Alcohol depresses the nervous system fast in a small animal. Raw dough is doubly dangerous: the warm stomach is an ideal fermenting environment, so the yeast both expands (causing painful bloating) and produces alcohol the cat then absorbs.
The “not poison, but not okay” group
Some foods won’t send you to the ER but still don’t belong in a cat’s bowl.
Dog food is the classic example. A stolen kibble or two is harmless, but cats are obligate carnivores with needs dog food isn’t designed to meet — most importantly taurine, an amino acid cats can’t make in adequate amounts. Chronic taurine deficiency can cause serious heart disease (dilated cardiomyopathy) and vision loss. Vitamin A and protein levels also fall short. International Cat Care and Merck both stress that “cat food for cats” isn’t marketing — it’s nutrition.
Tuna in excess is a similar story. As an occasional treat, canned tuna is fine. As a dietary staple, it’s unbalanced and can displace complete nutrition. Some cats also become so fond of it they refuse balanced food — a behavioral trap as much as a nutritional one.
Milk and dairy are widely misunderstood. The saucer-of-milk image is charming but outdated: most adult cats are lactose intolerant and lack the enzyme to digest milk sugar, so dairy tends to cause diarrhea and stomach upset. It’s not toxic — just a common cause of a messy litter box.
Raw fish can contain thiaminase, an enzyme that breaks down thiamine (vitamin B1). An occasional bit is unlikely to cause harm, but a diet heavy in certain raw fish can lead to thiamine deficiency, which affects the nervous system. Cooking deactivates the enzyme.
If you’re building meals at home rather than relying on commercial food, the taurine, vitamin, and thiamine issues above are exactly the gaps to plan around — our homemade cat food guide walks through how to do it safely.
A critical aside: lilies aren’t a food, but they’re an emergency
This guide is about foods, but it would be irresponsible to leave out lilies, because they cause more feline emergencies than almost anything in the kitchen. True lilies (Lilium and Hemerocallis — Easter, Tiger, Asiatic, daylilies) are exquisitely toxic to cats: even nibbling a leaf, a petal, or drinking the vase water can trigger acute kidney failure. The ASPCA APCC treats lily exposure as a true emergency. If a lily is in your home and your cat has access to it, call poison control even before symptoms appear.
If your cat ate something toxic
Act quickly, and don’t wait to see whether symptoms develop — with several of these toxins, early treatment changes the outcome.
- Call for help right away. Contact your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435 (a consultation fee may apply). They’re available around the clock and can tell you whether what your cat ate is a genuine risk.
- Gather the details. Note what was eaten, roughly how much, and when. Keep the packaging or a photo of the ingredient list — knowing exactly what’s in a product speeds up the advice you get.
- Don’t induce vomiting on your own. Making a cat vomit can do more harm than good, and some substances are dangerous coming back up. Only do it if a veterinary professional instructs you to.
When in doubt, make the call. A few minutes on the phone with a professional is far cheaper than a guess that goes wrong — and most of the time, you’ll be reassured that the bite your cat stole was nothing to worry about.