VeterUSA · Emergency triage
Did your pet eat onion or garlic?
Onion, garlic, chives, and leeks (the Allium family) damage pets' red blood cells. Hidden sources matter most: soup and gravy mixes, garlic bread, baby food, and seasoned leftovers. Enter what you know for a risk level.
Garlic and powders pack a much bigger punch than fresh onion — and cats are more sensitive than dogs. Signs can be delayed several days, so don't judge by how your pet looks right now.
Rough reference
- 1 medium onion~110 g
- 1 cup chopped onion~160 g
- 1 garlic clove~4 g
- 1 tsp onion powder~2.5 g
- 1 tsp garlic powder~3 g
Garlic supplements and soup/dip mixes are very concentrated — a small amount can matter. If unsure, estimate high and call.
Both helplines are staffed 24/7 by veterinary toxicologists. A consultation fee may apply. If your pet has pale or yellow gums, weakness, fast breathing, or red/brown urine, skip the calculator and go to the nearest ER now.
How onion and garlic poisoning works
Onions, garlic, chives, and leeks contain sulfur compounds that damage the membranes of red blood cells. This creates "Heinz bodies," can convert the blood's oxygen-carrier into a useless form (methemoglobin), and leads to the destruction of red blood cells — a hemolytic anemia. The result can be weakness, pale or yellow gums, fast breathing, and red- or brown-tinged urine, often developing over several days rather than right away.
How much is toxic
For raw onion, signs are generally linked to about 5 g per kg of body weight in cats and 15–30 g/kg in dogs. Garlic is roughly 4–5× more potent than onion, and dried powders are far more concentrated than fresh (the water is gone), so a teaspoon of garlic powder is much more dangerous than it looks. This calculator converts what you entered into an "onion-equivalent" dose to compare against those thresholds — it's an estimate, not a guarantee.
Cats and small/repeated doses
Cats are more sensitive than dogs, so smaller amounts matter more. Toxicity can also build up from repeated small amounts (for example, daily table scraps or garlic supplements), not just one big meal. When in doubt — especially with concentrated products or cats — call.
Is this calculator a substitute for a vet?
No. It estimates urgency from established thresholds, but real-world products vary and individual pets differ. For concentrated forms, cats, or any uncertainty, call a veterinarian or an animal poison control line rather than wait.