Dogs & cats · Free tool

Onion & garlic toxicity calculator

Check an estimated exposure by weight, type and amount. If any detail is unknown, contact your vet or a poison specialist.

Possible poisoning? Call your vet now. You do not need a calculation to get help.

Pet Poison Helpline (855) 764-7661ASPCA Animal Poison Control (888) 426-4435

Estimate for triage only, based on Allium toxicity thresholds from the Merck Veterinary Manual and ASPCA Animal Poison Control. Thresholds are set to the more-sensitive cat, and toxicity also depends on the individual pet and repeated exposure — so a low estimate never means "safe." When in doubt, call.

Sources: Merck Veterinary Manual — Allium species (Onions, Garlic) Toxicosis in Animals; ASPCA Animal Poison Control — People Foods to Avoid Feeding Your Pets

Onion, garlic, leeks, and chives (the Allium family) can damage a pet's red blood cells and cause anemia. Garlic is several times more potent than onion. Cooking does not make them safe, and dried powders can be concentrated. Cats are more sensitive than dogs, and signs are often delayed. This tool estimates known raw onion or garlic exposures using conservative thresholds; cooked foods, powders and uncertain details need an individual assessment from your vet or a pet poison line.

How much onion or garlic is too much?

Each cell is roughly the amount at which this tool starts telling you to call — 1 g/kg of onion-equivalent. Below a number here still isn't “safe”: it is the point at which concern begins, not the point at which harm does.

Amount of onion or garlic, by pet weight and type, at which this calculator's first warning band begins
WeightRaw onionRaw garlic
5 lb2 grams0.454 grams
10 lb4 grams0.907 grams
20 lb9 grams1 gram
40 lb18 grams3 grams
70 lb31 grams6 grams

Rounded from the same thresholds the calculator above uses. Individual sensitivity, other ingredients, and your pet's health all move the real number — which is why every band here still ends in “call.”

Common questions

How much onion or garlic is toxic to dogs and cats?

Red-blood-cell damage is expected at around 5 grams of onion per kilogram of body weight in a cat, and dogs are affected at higher amounts — but sensitivity varies and the effect builds with repeated exposure, so this calculator starts flagging concern from about 1 g/kg. Garlic is roughly five times stronger than onion, and powders are far more concentrated still, so even small amounts of garlic powder in seasoning or a small piece of garlic bread can matter for a cat or small dog.

Is garlic worse than onion for pets?

Yes — gram for gram, garlic is about five times more potent than onion, and dehydrated garlic or onion powder is more concentrated again. That's why a pinch of garlic powder in a recipe can be more of a concern than a similar weight of raw onion.

What are the signs of onion or garlic poisoning?

The hallmark is anemia from damaged red blood cells: tiredness, weakness, pale or yellowish gums, faster breathing, and reddish-brown urine. Vomiting or diarrhea can come first. The catch is timing — signs often don't appear for several days after eating, so a normal-looking pet today doesn't rule it out.

My pet ate a small amount of garlic — will they be okay?

Often a tiny, one-time taste causes no visible problem, but because cats and small dogs are sensitive and the effect is cumulative, it's worth noting the amount and your pet's weight and calling your vet or a pet poison line to check. Avoid giving any garlic or onion — including garlic supplements marketed for pets — without veterinary advice.

Read nextSymptoms, timeline, and what the vet will doThe full guide to onion or garlic — what to watch for and how long it takes to show.

More pet safety tools

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These tools estimate risk — they don't replace your veterinarian and can't examine your pet. For anything worrying, or when in doubt, get a free triage assessment or call your vet.