Can dogs eat?Reviewed: 2025-12-27~1 min

Can dogs eat onions after your dog ate onion-loaded stir-fry leftovers?

Short answer

ℹ️Quick answer

No. Onions in any form—including cooked, sautéed, or in stir-fry sauces—are unsafe for dogs.

Why people ask this

People often ask this right after their dog swiped onion-loaded stir-fry leftovers from the counter. Cooked onions mixed with sauces, garlic, or scallions can make it unclear how much onion was eaten. Stir-fries can also concentrate onion in reduced sauces and contain multiple alliums. Owners want to know if cooking makes onions safe (it doesn’t), what symptoms to watch for, and whether to call the vet immediately.

When it might be safe

There are no commonly accepted situations where this is considered safe.

When it is not safe

Cooked or caramelized onions from stir-fry (cooking does not reduce the toxic thiosulfates)
Onion powder or onion paste hidden in stir-fry sauces or marinades
Mixed alliums common in stir-fries (garlic, scallions, leeks) which add to the total dose
Leftover stir-fry where reduced sauce concentrates onion flavor and exposure
High-sodium soy-based sauces and chili oils that can worsen dehydration and GI upset

Possible risks

Thiosulfate-induced oxidative damage to red blood cells leading to hemolytic anemia (Heinz bodies)
Delayed onset of signs—often 6–72 hours after eating, sometimes up to several days post–stir-fry exposure
Early GI signs: drooling, vomiting, diarrhea, abdominal discomfort after rich, oily leftovers
Progressive signs: lethargy, pale gums, rapid breathing/heart rate, weakness, red-brown urine
Higher risk with small dogs or large intakes; mixed alliums and salty stir-fry sauces can compound effects

Safer alternatives

For a dog-safe ‘stir-fry’ vibe: plain cooked chicken or turkey with steamed carrots, green beans, or zucchini (no onions/garlic, no sauce)
Simple snacks after an incident: a small amount of plain white rice with unseasoned boiled chicken, or a few carrot/green bean pieces
Crunchy, low-risk veggies instead of onions: cucumber slices, bell pepper strips (seeded), or broccoli florets in small amounts
Commercial dog treats or kibble reserved before you cook, so you’re not tempted to share seasoned leftovers
If cooking for the household, set aside a plain portion before adding onions, garlic, sauces, or chili oil

Bottom line

Onions are unsafe for dogs even when cooked in stir-fry. Contact your vet or a pet poison helpline now if your dog ate onion-loaded leftovers. Estimate how much onion (fresh or powdered) might have been in the dish; toxic doses can be as low as ~15–30 g/kg for fresh onion (less for powders). Do not induce vomiting unless your vet instructs you. Monitor for vomiting, lethargy, pale gums, rapid breathing, or dark urine over the next 1–3 days, and bring the recipe or ingredient list to the appointment.