Can Cats Eat Onions?

☠️ Toxic

✅ Cross-checked against veterinary poison-control guidance · Oct 2026 audit

⚠️ Educational info only. If your pet just ate something and looks unwell, skip the reading and call your vet or Pet Poison Helpline (US): (855) 764-7661.

No. Onions are poisonous to cats in every form — raw, cooked, powdered or in broth.

Why it’s a problem

Onions contain N-propyl disulfide, a thiosulfate compound that oxidizes and destroys feline red blood cells, causing hemolytic anemia. Cats are several times more sensitive than dogs, and onion powder is the most concentrated form, hiding in soups, gravies, sauces and baby food.

How to serve it safely

Keep all allium dishes away from cats, check labels on leftovers and broths, and clean up dropped food — cats groom what they walk through.

Warning signs to watch for

Lethargy, weakness, pale or bluish gums, drooling, vomiting, rapid breathing and red or brown urine; anemia can worsen for days after ingestion.

When to call the vet

Call your vet the moment you know onions were eaten, even if the cat looks completely normal — treatment before symptoms is far more effective.

Common questions

Is a tiny piece of cooked onion in stew dangerous?

Yes, it can be. Cooking does not destroy the toxin and broth concentrates it. Cats are so sensitive that even small doses matter.

How quickly do symptoms appear?

Stomach upset can start within hours, but the anemia typically shows up 2 to 5 days later — which is why early vet contact matters.

More foods for cats

Salmon✅ SafeYes, when fully cooked and unseasoned. Salmon is a nutritious fish most cats enjoy.Tuna⚠️ In ModerationOccasional small amounts only — tuna should be a treat, never a meal.Cow’s Milk🚫 Not RecommendedBetter to skip it. Most adult cats are lactose intolerant and milk gives them stomach upset.Garlic☠️ ToxicNo. Garlic is poisonous to cats — even more potent per gram than onion.Cooked Eggs✅ SafeYes, fully cooked and plain. Eggs are a protein-rich treat cats usually enjoy.Cheese⚠️ In ModerationSmall bites are usually fine, but many cats cannot digest dairy well.

This page is general educational information, not a substitute for professional veterinary advice. Every pet is different — if your animal ate something concerning, contact your veterinarian or a pet poison hotline right away.