Dog Onion Toxicity Calculator
Enter your dog's weight and the approximate amount of onion (or related Allium food) eaten to see an exposure summary. This is an educational estimate only - if your dog has eaten onion, garlic, or a related food, contact a veterinarian or animal poison control promptly.
Last updated: September 23, 2026
Frequently asked questions
Is a small amount of onion definitely safe for dogs?
This tool doesn't establish any amount as definitely safe - onion and related Allium foods (garlic, leeks, chives, scallions) contain compounds that can damage a dog's red blood cells, and individual sensitivity, preparation method, and repeated smaller exposures over time can all affect risk in ways a single exposure calculation can't fully capture. Contact a veterinarian or poison control after any known ingestion rather than relying on a threshold.
Are cooked, powdered, or dehydrated onion more concentrated than raw onion?
Yes, generally - cooking, powdering, or dehydrating onion removes water and concentrates the compounds of concern by weight, so a given weight of onion powder or dehydrated onion can represent significantly more concentrated exposure than the same weight of raw onion. This is part of why ingredients like onion powder in cooked foods, soups, or baby food are a common accidental exposure source.
What should I do right now if my dog ate onion, garlic, or a related food?
Contact your veterinarian, an emergency animal hospital, or an animal poison control service immediately - don't wait to see if symptoms develop. Signs of onion/Allium toxicity can be delayed by several days as red blood cell damage progresses, so absence of immediate symptoms doesn't mean the ingestion wasn't significant. Don't attempt any home treatment unless a veterinary professional specifically instructs you to.
Does garlic carry the same risk as onion?
Garlic is in the same plant family (Allium) as onion and is generally considered to carry a similar or potentially greater risk per unit weight in dogs, though exact relative potency is debated - both should be treated with the same level of caution and prompt veterinary contact after ingestion.
Why doesn't this calculator give a specific 'toxic dose' number?
Onion/Allium toxicity in dogs doesn't have a single precise, universally agreed toxic dose the way some other toxins do - susceptibility varies by individual, and factors like the specific Allium species, preparation, and whether exposure is a one-time event or repeated over days all affect risk. This tool provides an exposure summary to aid a conversation with a veterinarian, not a threshold to self-diagnose against.
Can repeated small exposures to onion be a problem even if a single exposure seems minor?
Yes - because the toxic effect involves cumulative damage to red blood cells, repeated smaller exposures over time (such as regularly feeding table scraps containing onion or garlic powder) can add up to a meaningful risk even if no single incident looks large on its own.