Why
Onions, leeks and chives are in the Allium family. They irritate the gut and damage red blood cells, whether raw, cooked or powdered.
What to do instead
- Do not feed onion or foods cooked with it.
Safer swaps from the same group: carrots, celery, cucumbers, green beans.
Warning signs
- Signs include vomiting, diarrhea and stomach pain.
- Akitas and Shiba Inus are at higher risk.
If your dog ate onions
- Note how much your dog ate and when, and keep any packaging.
- Call your vet, an emergency clinic, ASPCA Animal Poison Control ((888) 426-4435) or the Pet Poison Helpline (855-764-7661).
- Don't make your dog vomit unless a vet tells you to.
Other vegetables: quick answers
| Food | Verdict | Short answer |
|---|---|---|
| Asparagus | Avoid | Not unsafe, but not worth it. Asparagus is tough raw and loses most of its value when cooked soft. |
| Mushrooms | Avoid | Store-bought mushrooms are generally fine, but wild mushrooms can be deadly. |
| Tomatoes | Avoid | Best avoided. Ripe flesh is generally safe, but the green parts of the plant contain a toxin. |
| Broccoli | Small amounts | Yes, in small amounts. Cooked florets are easiest on the stomach. |
| Brussels sprouts | Small amounts | Yes, a few cooked sprouts. Expect gas. |
| Corn | Small amounts | Yes, off the cob. The cob can cause a dangerous blockage. |
| Peas | Small amounts | Yes, plain green peas in moderation. |
| Potatoes | Small amounts | Yes, plain and fully cooked, as an occasional extra. Never green or raw. |
Rules for any new food
- Plain is the rule: no salt, butter, oil, onion, garlic, sugar or sweeteners. Most of the danger in human food comes from what is added to it.
- Keep all treats under 10% of your dog's daily calories (WSAVA). The rest should come from a complete dog food.
- Check labels for xylitol, raisins, chocolate and macadamia nuts, which turn up in baked goods, snacks and spreads.
- If your dog has a health condition, such as diabetes, pancreatitis or kidney disease, ask your vet before adding any new food.
Frequently asked questions
Are onions safe for dogs?
No. Onions can rupture red blood cells and cause anemia.
What should I do if my dog ate onions?
Call your vet, an emergency clinic, or ASPCA Animal Poison Control at (888) 426-4435 right away. Note how much your dog ate and when.
Sources
- American Kennel Club, "Fruits and Vegetables Dogs Can and Can't Eat" (updated Aug 4, 2026)
- ASPCA Animal Poison Control, "People Foods to Avoid Feeding Your Pets"
Checked October 17, 2026. We are a reference, not a vet: if in doubt, call yours. How we check.