25 Common Human Foods That Are Toxic to Dogs and Cats

Most pet poisoning cases don't involve anything exotic — they involve food that was already sitting in the kitchen. A dropped grape, a counter-surfed chocolate bar, a "harmless" bite of onion-seasoned leftovers. Because dogs and cats metabolize certain compounds completely differently than humans do, foods that are perfectly fine for us can range from mildly upsetting to life-threatening for them.

This list covers the most common offenders, why they're dangerous, and what to actually do if your pet eats one.

Foods That Are Dangerous for Both Dogs and Cats

1. Chocolate — Contains theobromine and caffeine, which pets metabolize far more slowly than humans. Darker, more concentrated chocolate (baking chocolate, dark chocolate, cocoa powder) is more dangerous than milk chocolate. Symptoms include vomiting, restlessness, a racing heart, tremors, and in severe cases seizures.

2. Grapes and Raisins — Can cause acute kidney failure in dogs, even in small amounts, and the mechanism still isn't fully understood — which is part of why there's no known "safe" quantity. Cats are less commonly reported but are not considered safe either.

3. Onions, Garlic, Chives, and Leeks (the Allium family) — Damage red blood cells and can cause a type of anemia. Risk applies to raw, cooked, powdered, and dehydrated forms alike — including onion powder in seasoned leftovers, soups, and baby food.

4. Xylitol — An artificial sweetener found in sugar-free gum, some peanut butters, baked goods, and toothpaste. In dogs, it triggers a dangerous insulin spike leading to hypoglycemia, and at higher doses, liver failure. It is one of the fastest-acting and most serious items on this list.

5. Alcohol — Even small amounts can cause vomiting, disorientation, dangerously low body temperature, and respiratory depression, in part because of body-size differences.

6. Caffeine (coffee, tea, energy drinks, coffee grounds) — Similar mechanism to chocolate; affects the heart and nervous system.

7. Raw Yeast Dough — Continues to rise in a warm stomach, causing painful bloating and potentially releasing alcohol as it ferments.

8. Macadamia Nuts — A dog-specific toxin causing weakness, tremors, and hyperthermia, typically resolving within 24–48 hours but still requiring monitoring.

9. Excess Salt / Salty Snack Foods — Large quantities can lead to sodium ion poisoning, especially dangerous for smaller pets.

Foods That Are More of a Concern for Cats Specifically

10. Raw Dough Containing Onion/Garlic Seasoning — Compounds risk when both irritant categories are present.

11. Lilies (not a food, but frequently ingested by cats who chew houseplants) — Even small amounts of pollen or leaf can cause acute kidney failure in cats. Worth a mention here because it's one of the most under-recognized cat-specific risks.

Foods That Are Risky Mainly Because of How They're Prepared

12. Cooked Bones — Cooking makes bones brittle and prone to splintering, creating a choking or internal injury risk that raw bones (fed appropriately) don't carry in the same way.

13. Fatty Table Scraps / Skin, Trimmed Fat — A common trigger for pancreatitis, particularly around holidays when rich food is more available.

14. Avocado — The flesh is a lower risk for dogs and cats than for birds and some livestock, but the pit is a genuine choking/obstruction hazard, and the skin contains persin, which can still cause GI upset.

15. Unripe Tomatoes and Tomato Plant Leaves/Stems — Contain solanine, which drops to safe levels once the tomato ripens, but green parts and unripe fruit carry more risk.

16. Raw Potato / Green Potato Skin — Also a solanine source; cooked, ripe potato flesh is generally fine in small amounts, raw or green potato is not.

Milder but Still Worth Avoiding

17. Cow's Milk and Dairy — Most adult dogs and cats are lactose intolerant to some degree; not toxic, but a common cause of GI upset.

18. Cinnamon (large quantities) — Can irritate the mouth and GI tract; essential oil forms are more concentrated and more risky than the ground spice used in baking.

19. Nutmeg — Contains myristicin, which in larger amounts can affect the nervous system.

20. Citrus Fruit Peels, Pith, and Seeds — The essential oils and compounds in the peel/pith are more of an irritant than the fruit flesh itself.

21–25. Mold-Contaminated Food of Any Kind — Certain molds that grow on old bread, cheese, nuts, and dairy produce tremorgenic mycotoxins that can cause severe tremors and seizures. When in doubt about anything moldy, don't offer it.

What To Do If Your Pet Eats Something on This List

1. Don't wait for symptoms to appear before acting — for some of these (grapes, xylitol especially), by the time symptoms show up, organ damage may already be underway.
2. Note what was eaten, roughly how much, and when — this single piece of information matters more than almost anything else for a fast, correct response.
3. Contact your veterinarian or an animal poison control hotline immediately rather than searching for home remedies — inducing vomiting is not safe in every situation (for example, after ingesting something caustic or sharp), and a professional needs to make that call based on what was actually eaten.
4. Bring the packaging if you can — knowing the exact product (and its xylitol/theobromine content, if listed) speeds up treatment decisions significantly.

Building a Habit of Checking Before Sharing

The single most effective habit for preventing food-related emergencies is a simple pause: before a scrap of table food or a dropped item gets handed over (or before it hits the floor and gets vacuumed up in three seconds by an opportunistic dog), take five seconds to think about what's actually in it.

Because that pause only works if you can act on it quickly, PawOptima Steward includes an offline toxin lookup covering hundreds of common human foods and household items, so you can check something in seconds — no internet connection required, no waiting on a search engine while your pet is already sniffing at whatever fell on the floor.

The Bottom Line

Most of the foods on this list are things that are already in your kitchen right now. The risk isn't exotic — it's routine. A little awareness about which everyday items are actually dangerous, and a fast way to check when you're not sure, goes a long way toward preventing an emergency vet visit.

This article is for general educational purposes and is not a substitute for guidance from your veterinarian or a professional animal poison control service. If you believe your pet has ingested something toxic, contact a veterinary professional immediately.