How much onion is toxic to dogs?

There is no safe dose. Toxicity varies by size and type (onion, garlic, powders). This calculator uses conservative VPIS-style bands — always phone your vet after any ingestion.

Are cats more sensitive to onion and garlic?

Yes. Cats are generally more susceptible to Allium toxicity than dogs. Even small amounts in table scraps or seasoned food warrant a call to your vet.

Quick answer

The free PETHEALTH+ calculator estimates onion-equivalent dose from your pet's weight and what was eaten. Allium toxicity can cause delayed red blood cell damage — always phone your vet after any ingestion, even if the result looks low.

Onion & garlic toxicity calculator

Onion, garlic, chives and powders can damage red blood cells in dogs and cats. Signs may be delayed by several days — always phone your vet if your pet ate any amount.

Based on published Allium toxicity thresholds used in UK veterinary toxicology triage. Not a substitute for veterinary advice. Read our full onion & garlic poisoning guide.

Frequently Asked Questions

How much onion is toxic to dogs?: There is no safe dose. Toxicity varies by size and type (onion, garlic, powders). This calculator uses conservative VPIS-style bands — always phone your vet after any ingestion.
Are cats more sensitive to onion and garlic?: Yes. Cats are generally more susceptible to Allium toxicity than dogs. Even small amounts in table scraps or seasoned food warrant a call to your vet.