Dog Onion & Garlic Toxicity Calculator
Dog got into onion, garlic, leek or chives — fresh, cooked or powdered? Enter their weight and how much to see the risk level and what to do next.
Cooking, frying or powdering does NOT destroy the toxin.
Enter your dog's weight and how much they had to see the risk.
- ASPCA Animal Poison Control: (888) 426-4435 · US (fee may apply)
- Pet Poison Helpline: (855) 764-7661 · US/Canada (fee may apply)
This is an estimate to help you decide whether to call, not a diagnosis. When the amount is uncertain or your pet is small, young or unwell, treat it as more serious and pick up the phone.
Estimate only — not veterinary advice. Every animal is different; for a medication dose, a possible poisoning, or any emergency, call your veterinarian or an animal poison control line right away.
How the dose is worked out
Onions, garlic, leeks and chives are all Alliumplants. They contain compounds (organosulfur thiosulfinates) that dogs can't safely process — these attack red blood cells and can cause hemolytic anemia. Risk is driven by dose. Because garlic is roughly five times stronger than onion, and powders are concentrated, this tool converts whatever your dog ate into an onion-equivalent amount per kilogram of body weight, then maps it to a risk level. Trouble climbs as you approach about 5 g/kg of onion-equivalent.
Why the danger is delayed
Unlike chocolate or xylitol, onion and garlic rarely cause a dramatic reaction in the first hours. The red-blood-cell damage builds over one to five days, so a dog can seem fine right after eating and then become weak, pale and breathless later in the week. That delay is exactly why you shouldn't wait for symptoms to decide whether it mattered — run the numbers and call if the amount was meaningful.
What to do right now
- Note the source (onion, garlic, powder, soup) and a best guess of the amount.
- Call your vet or a poison line (ASPCA 888-426-4435, Pet Poison Helpline 855-764-7661).
- Watch for several days — pale or yellow gums, weakness, fast breathing and dark urine.
- Stop ongoing exposure: check table scraps, seasoned leftovers and any treats with garlic.
Frequently asked questions
- How much onion or garlic is toxic to a dog?
- Damage to red blood cells becomes a real risk around 5 grams of onion per kilogram of body weight — roughly a medium onion for a 10 kg (22 lb) dog. Garlic is far stronger, about five times more potent gram for gram, so it takes much less. Powders and seasonings are dehydrated and concentrated, so they count for more than they look.
- Is a little garlic actually bad for dogs?
- A tiny amount once is unlikely to cause obvious harm, which is why some treats contain trace garlic. The problem is dose and repetition: regular or larger servings build up and damage red blood cells. Because garlic is so concentrated it's easy to overshoot — this calculator helps you see where a given amount lands.
- What about onion powder, soup or baby food?
- These are common hidden sources. Onion and garlic powder are dehydrated, so a teaspoon carries far more than it seems. Many soups, gravies, broths, stir-fries and even some baby foods are seasoned with them — a dog that licks a plate or bowl clean can get a meaningful dose.
- What are the symptoms of onion or garlic poisoning?
- They're delayed. Allium toxins damage red blood cells over 1–5 days, so early on you may see only vomiting, diarrhea or a sore tummy. Then the anemia shows: tiredness, weakness, pale or yellow gums, fast breathing or heart rate, and reddish-brown urine. Call your vet if your dog ate a meaningful amount, even if they seem fine right now.
- Are cats affected too?
- Yes — cats are even more sensitive to onions and garlic than dogs. This calculator is set up for dogs; if a cat ate any onion or garlic, treat it seriously and call your vet or a poison line.
Sources
These are the references behind this calculator. Where a source gives a range we take the midpoint and round toward caution, and where we go beyond what a source states — an extra safety margin, or a rule of thumb rather than a clinical threshold — the page says so in the text above.
- Onion — Pet Poison Helpline
- Garlic — Pet Poison Helpline
- People foods to avoid feeding your pets — ASPCA