Five foods account for most serious poisonings in dogs and cats: chocolate, xylitol, grapes and raisins, onions and garlic, and alcohol. If your pet has just eaten one of them, stop reading and call a veterinarian or a poison control line. Everything below is for the other situation, the one where you want to know before it happens.
The short answer
- The most dangerous common foods are xylitol, grapes and raisins, chocolate, onions and garlic, and alcohol.
- Do not wait for symptoms. With xylitol and grapes, damage starts before an animal looks unwell.
- Do not induce vomiting unless a veterinarian tells you to. It makes some poisonings worse.
- Have ready: your pet's weight, what it ate, roughly how much, and when. That is what a poison line asks for.
- Some famous items are overstated. Avocado is mainly a bird and rabbit problem, not a dog one.
If it already happened
Do this in order, and do it now rather than after searching further:
- Take the food away and keep the packaging. The ingredient list matters more than the brand.
- Do not make your pet vomit on your own initiative. For some substances that causes more harm.
- Call a vet or a poison control service. In the US, ASPCA Animal Poison Control and Pet Poison Helpline both operate 24 hours. Outside the US, call your own clinic or its emergency number.
- Have four facts ready: species and weight, what was eaten, an estimate of the amount, and the time.
- Go in if you are told to go in. Most of these are treatable when treated early and much harder once symptoms are established.
Quick reference
| Food | Risk level | What it does |
|---|---|---|
| Xylitol (birch sugar) | Severe | Sudden low blood sugar; liver damage within 12 to 24 hours |
| Grapes, raisins, sultanas | Severe | Kidney damage; no reliably safe amount is known |
| Chocolate, coffee, caffeine | High | Methylxanthines: vomiting, racing heart, tremors, seizures |
| Onion, garlic, chives, leek | High | Damages red blood cells, causing anaemia; cats more susceptible |
| Alcohol and raw yeast dough | High | Alcohol poisoning; dough expands in the stomach and can twist it |
| Macadamia nuts | Moderate, dogs | Weakness, tremors, raised temperature within 12 hours |
| Excess salt | Moderate | Vomiting, tremors, seizures at high intake |
| Raw meat, raw eggs, bones | Moderate | Salmonella and E. coli; bones can obstruct or perforate the gut |
| Fatty foods and most nuts | Moderate | Pancreatitis, which can be serious in its own right |
| Milk and dairy | Low | Not toxic. Most adult pets lack lactase, so it causes diarrhoea |
The serious ones, explained
Xylitol
The most underestimated item on the list, because it hides in ordinary products: sugar-free gum, mints, some peanut butters, baked goods, toothpaste, and supplements. It may be labelled birch sugar or E967.
In dogs it triggers a rapid insulin release and blood sugar can crash within 15 to 30 minutes. Liver damage can follow over 12 to 24 hours. Signs start as vomiting, lethargy and wobbliness and can progress to seizures. This is a same-hour emergency, not a wait-and-see.
Grapes and raisins
Grapes, raisins, sultanas and currants can cause acute kidney injury in dogs. Tartaric acid is the suspected culprit, and the crucial detail for owners is that susceptibility varies enormously between individuals. Some dogs eat a handful without harm; others develop kidney failure from a small amount. Because there is no reliable dose threshold, the standard advice is to treat any ingestion as worth a phone call.
Chocolate, coffee and caffeine
These share a group of compounds called methylxanthines. The concentration is what matters: white chocolate has very little, milk chocolate more, and dark chocolate, baking chocolate and cocoa powder the most. A biscuit with a milk chocolate coating and an equal weight of cocoa powder are not the same event.
Signs include vomiting, diarrhoea, panting, excessive thirst and urination, restlessness, abnormal heart rhythm, tremors and seizures. Do not try to calculate a safe dose at home. Give the weight, the type of chocolate and the amount to a poison line and let them do it.
Onions, garlic, chives and leeks
All are Allium species, and all damage red blood cells, which can lead to anaemia. Cats are more susceptible than dogs, but both are at risk depending on the amount. Cooking does not remove the risk, which is why the usual route is not a raw onion but leftovers: onion gravy, stew, garlic bread, baby food containing onion powder. Powdered forms are the most concentrated.
Signs may be delayed by several days and look like weakness, pale gums and dark urine rather than an upset stomach.
Alcohol and raw yeast dough
Alcohol is absorbed quickly and causes vomiting, incoordination, breathing difficulty, tremors and in severe cases coma. Raw bread dough is two problems at once: it expands in the warm stomach, which is painful and can cause the stomach to bloat and twist, and the fermenting yeast produces alcohol internally.
Macadamia nuts
Specific to dogs, and distinctive: weakness, particularly in the hind legs, incoordination, vomiting, tremors and raised body temperature, typically within 12 hours and usually resolving in 24 to 72 hours with supportive care.
Risky but not poisonous
Worth separating, because lists that treat everything as lethal train people to ignore the whole list.
- Milk and dairy are not toxic. Most adult dogs and cats produce little lactase, so the result is diarrhoea, not poisoning.
- Most nuts (almonds, pecans, walnuts) are a fat and obstruction problem rather than a toxicity one, though the fat load can trigger pancreatitis.
- Citrus flesh in small amounts causes at most mild stomach upset. The oils in peel and leaves are the more irritating part.
- Coconut in small amounts is unlikely to cause serious harm, though the oils can loosen stools.
The avocado misunderstanding
Avocado appears on nearly every toxic-foods list, usually without qualification. The accurate version is narrower: persin is primarily a danger to birds and rabbits, where it can cause cardiovascular damage and death, and to horses, donkeys and ruminants, which can develop head and neck swelling.
For dogs and cats the flesh is not considered a significant toxin. The real avocado risks for them are the high fat content, which can upset a stomach or contribute to pancreatitis, and the stone, which is a classic cause of intestinal obstruction. If you keep birds or rabbits, treat avocado as genuinely dangerous. If you have a dog that stole a slice of guacamole, the onion and garlic in it matter more than the avocado.
Why how much is usually the wrong question
Owners ask for a threshold, and for most items on this list there isn't a useful one to apply at home. Three reasons:
- Concentration varies wildly. Cocoa powder and white chocolate differ by more than an order of magnitude.
- Individual susceptibility varies. Grapes are the clearest example: the same amount harms one dog and not another.
- Body weight changes everything. An amount that is trivial for a 40 kg dog can be serious for a 4 kg cat.
A poison control service does this calculation for a living, with the current product data in front of them. That call is the shortcut, not the obstacle.
What differs between cats and dogs
Dogs eat more of everything, so they dominate poisoning statistics, but cats are not safer by nature. Cats are more sensitive to Allium species and to salt, are much smaller, which lowers every threshold, and are less likely to show early signs, since hiding illness is normal feline behaviour. Our guide on signs your cat is sick covers what that concealment looks like in practice, and signs your dog is in pain does the same for dogs.
Prevention that actually works
Bins with lids that close. Handbags off the floor, since sugar-free gum lives in handbags. Chocolate and baked goods out of counter-surfing range. A house rule that nobody feeds leftovers without asking. Guests told once, clearly, rather than assumed to know.
And keep the numbers where you can find them at 2 a.m.: your clinic, its out-of-hours line, and a poison control service. PetVitals stores your pet's weight and current medication, which are the first two things a poison line asks for and the two things hardest to recall under stress. If you are new to keeping records at all, what a pet care app is explains the basics.
This article is general educational information, not veterinary advice, and it cannot tell you whether a specific amount is dangerous for a specific animal. If you suspect your pet has eaten something toxic, contact a veterinarian or a poison control service immediately.