Several common household foods can poison cats and dogs, sometimes in surprisingly small amounts. Chocolate, grapes, onions, garlic, xylitol, macadamia nuts, alcohol, and raw yeast dough top the list. Human food and drinks account for about 16% of all pet poison exposures reported to the ASPCA, making them the second most common category after medications.
Here’s what you need to know about each one, including how much it takes to cause harm and what symptoms look like.
Chocolate and Caffeine
Chocolate contains two stimulant compounds that dogs and cats cannot metabolize efficiently. The lethal dose for dogs is 100 to 500 mg per kilogram of body weight, but symptoms like vomiting, rapid heart rate, and restlessness can appear at much lower amounts. The danger depends heavily on the type of chocolate. Cocoa powder is the most concentrated at roughly 20 mg of the toxic compound per gram, followed by dark or plain chocolate at 15 mg/g. Milk chocolate contains far less at 2 mg/g, and white chocolate is nearly negligible at 0.1 mg/g.
To put that in practical terms, a 10-kilogram dog (about 22 pounds) could reach a dangerous dose from a single baking chocolate bar, while it would take a much larger quantity of milk chocolate to cause the same effect. Cats are also susceptible, though they encounter chocolate less often because they can’t taste sweetness. Coffee, tea, energy drinks, and caffeine pills carry the same type of risk.
Grapes and Raisins
Grapes and raisins can cause acute kidney failure in dogs, and the mechanism is still not fully understood. Scientists have proposed several theories, from naturally occurring compounds in the fruit to pesticide contamination, but none have been confirmed. What makes grapes especially dangerous is the unpredictability: some dogs eat a few and develop severe kidney injury, while others seem unaffected. There is no established safe threshold.
The lowest reported dose linked to kidney damage is about 20 grams of grapes per kilogram of body weight, and just 2.8 g/kg for raisins (which are more concentrated). For a 10-kg dog, that’s roughly a small handful of raisins. Because the toxic dose varies so widely between individual dogs and no one can predict which dogs will react, any amount should be treated as potentially dangerous. Currants and sultanas carry the same risk.
Onions and Garlic
All plants in the allium family, including onions, garlic, leeks, chives, and shallots, damage red blood cells in both cats and dogs. Sulfur-containing compounds in these foods cause the blood cells to break down, leading to a type of anemia. The damage begins within 24 hours and peaks around 72 hours after ingestion.
Cats are particularly sensitive. Toxicity has been reported in cats after eating less than a teaspoon of cooked onion, or about 5 grams of raw onion per kilogram of body weight. Dogs need a larger dose to show problems, typically 15 to 30 g/kg of raw onion. Garlic is three to five times more toxic than onion by weight. The most dangerous forms are concentrated ones: dehydrated flakes, powders, and dry soup mixes, because they pack far more allium compounds per serving than fresh bulbs. A small amount of garlic powder sprinkled on leftovers can be more harmful than a chunk of raw onion.
Symptoms include lethargy, pale gums, rapid breathing, and dark-colored urine. These can take a day or more to develop, so a dog or cat that seems fine right after eating something with onion isn’t necessarily in the clear.
Xylitol (Birch Sugar)
Xylitol is a sugar substitute found in sugar-free gum, mints, protein bars, peanut butter, baked goods, and some medications. It is extremely toxic to dogs. Dogs that ingest more than 0.1 grams per kilogram of body weight are at risk for a dangerous drop in blood sugar. At doses above 0.5 g/kg, acute liver failure becomes a concern.
A single stick of xylitol-sweetened gum can contain 0.3 to 1 gram of xylitol, meaning just one or two pieces could be enough to cause hypoglycemia in a small dog. Symptoms include vomiting, weakness, loss of coordination, and collapse, sometimes within 30 minutes. If you keep sugar-free products in the house, check labels for xylitol (also listed as “birch sugar” or “birch sap”) and store them well out of reach.
Macadamia Nuts
Macadamia nuts cause a distinctive set of symptoms in dogs: hind-leg weakness, tremors, vomiting, fever, and depression. In experimental cases, dogs given 20 grams per kilogram of body weight developed an inability to stand within 12 hours, along with rectal temperatures reaching 40.5°C (about 105°F). The average amount eaten in reported poisoning cases was around 12 g/kg.
The good news is that macadamia nut toxicity is rarely fatal in dogs and most recover within 24 to 48 hours. The bad news is that the symptoms can look alarming, and macadamia nuts are often found in cookies or trail mixes that also contain chocolate, compounding the danger. Cats don’t appear to be commonly affected, but limited data exists.
Alcohol and Raw Yeast Dough
Alcohol is toxic to pets in the same way it is to humans, just at much lower doses because of their smaller size. Beer, wine, liquor, and rum-soaked desserts all pose a risk. But the more surprising source is raw bread dough. When a dog swallows unbaked yeast dough, the warm environment of the stomach causes it to keep rising, which creates two problems at once: the expanding dough can cause dangerous bloating or gastric obstruction, and the fermenting yeast produces ethanol, essentially brewing alcohol inside the animal’s stomach.
Dogs that have eaten raw dough have shown vomiting, loss of coordination, blindness, dangerously low body temperature, and an inability to stand. The combination of physical distension and alcohol poisoning makes this a genuine emergency.
High-Fat Foods and Table Scraps
Fatty foods like bacon grease, turkey skin, butter, and fried leftovers are commonly shared with pets, especially around holidays. While the relationship between dietary fat and pancreatitis in dogs is more nuanced than once believed, sudden dietary shifts appear to be a significant risk factor. A dog that normally eats kibble and then gets a plate of Thanksgiving drippings is at higher risk than one that regularly eats a moderate-fat diet.
Dogs with already elevated blood triglyceride levels are especially vulnerable. Miniature Schnauzers with severely high triglycerides, for example, are 4.5 times more likely to show signs of pancreatic injury compared to those with normal levels. Pancreatitis causes severe abdominal pain, vomiting, and loss of appetite, and can require hospitalization. The safest approach is to avoid giving pets large amounts of rich food they aren’t accustomed to.
Avocado
Avocados contain a compound called persin, found in the fruit, pit, skin, and leaves. The toxicity risk varies dramatically by species. Birds are highly sensitive and can die from small amounts. Livestock like goats and sheep can develop heart damage from repeated exposure. For dogs and cats specifically, the risk from the flesh of a ripe avocado is considered low compared to these other animals. The bigger mechanical danger is the large pit, which can cause choking or a bowel obstruction if swallowed.
What to Do if Your Pet Eats Something Toxic
Speed matters, but the right response depends on what was eaten. Do not try to make your pet vomit without professional guidance. Inducing vomiting is sometimes the right move, but in other situations it can make things worse or is outright contraindicated.
Call your veterinarian or local emergency veterinary clinic immediately. If you can, tell them the brand name or ingredient list, how much your pet ate, when they ate it, and your pet’s approximate weight. This information helps determine how critical the situation is and whether home treatment is appropriate. If you can’t reach a vet, the ASPCA Poison Control Hotline (888-426-4435) and the Pet Poison Helpline (855-764-7661) are available around the clock and can walk you through first-aid steps over the phone.
If your pet is rapidly deteriorating, showing severe vomiting, collapse, or difficulty breathing, skip the phone call and go directly to the nearest emergency veterinary clinic.