🧅🧄 Onion & Garlic Toxicity Calculator
Your dog or cat got into onion, garlic, chives or leeks? Check the risk in seconds, then act. Built by a vet.
🐾 Who are we checking?
Onion & garlic poisoning is delayed. Red-blood-cell damage and anaemia often don't show for 1 to 5 days. A pet that looks fine right now can still be poisoned. When the number is borderline, treat it as the higher risk and call.
⚠️ Why onion & garlic are dangerous
Every part of the onion/garlic family (Allium) — onion, garlic, chives, leeks and shallots — contains sulfur compounds that damage red blood cells. The result is Heinz-body haemolytic anaemia: the red cells rupture and the pet can't carry oxygen properly.
Cooking, drying or powdering does not make it safe. Powders and dehydrated flakes are the most dangerous because the toxin is concentrated. Garlic is roughly 3–5× more toxic than onion gram for gram.
Cats are the most sensitive species, followed by dogs. Japanese dog breeds such as Akitas and Shiba Inus can be extra vulnerable.
⚖️ Rough weights (for reference)
| Item | Approx. weight |
|---|---|
| Medium onion | ~110 g |
| Garlic clove | ~4 g |
| 1 tsp garlic powder | ~3 g (≈ 8 fresh cloves) |
| 1 tsp onion powder | ~2.5 g |
🚑 Warning signs to watch (1–5 days)
Vomiting, diarrhoea, drooling or belly pain early on. Then lethargy, weakness, pale or yellow gums, fast breathing, racing heart, red-brown urine or collapse. These signal anaemia and are an emergency.
🧮 How this calculator works
It converts what your pet ate into an onion-equivalent dose per kilogram of body weight, adjusting for garlic potency and concentrated powders. It then compares that result with the calculator's risk bands. Cats and Japanese breeds are scored more conservatively. It is a guide to help you act fast, not a diagnosis.
🤔 My pet ate a tiny bit — do I still need to worry?
A single small lick of gravy or one stray ring is usually low risk for a large dog, but risk is never zero for a cat or a small pet, and repeated small amounts can add up. Because signs are delayed, call your vet or a pet poison line whenever you are unsure.
🏥 What will the vet do?
If exposure was recent, the vet may induce vomiting and consider decontamination. Blood tests may be repeated over several days because anaemia is delayed. Severe cases may need fluids, oxygen or a transfusion. Early action makes a major difference.
This calculator is an educational guide from ASK A VET™ and does not replace an in-person veterinary assessment or a poison-control service. Doses are estimates and real cases vary. If you suspect poisoning, contact your veterinarian or an animal poison-control service immediately.