Can cats eat onions?
nutritioncatstoxic foods
No, cats cannot eat onions. Onions are extremely toxic to cats — even more so than to dogs. Cats are particularly sensitive to the toxic compounds found in onions.
Why is it so dangerous?
Onions contain disulfides and thiosulfates that destroy cats’ red blood cells, causing hemolytic anemia. Cats are more vulnerable because their red blood cells are more susceptible to oxidative damage.
All forms are dangerous
- Raw, cooked, fried, dehydrated, powdered
- Onion powder is especially dangerous — more concentrated and present in many human foods
- Even onion broth can cause poisoning
Dangerous amounts
Just 5g of onion per kg of body weight can be toxic to cats. For a 4kg (9lb) cat, that’s less than a tablespoon. Toxicity is also cumulative — small doses over several days are equally dangerous.
The entire Allium family is toxic
- Garlic — toxic (5x more toxic than onions for cats)
- Chives — toxic
- Leeks — toxic
- Shallots — toxic
Symptoms
May take 1 to 5 days to appear:
- Lethargy and weakness
- Loss of appetite
- Pale or yellowish gums
- Dark urine (brown or reddish)
- Rapid breathing
- Vomiting and diarrhea
- Elevated heart rate
What to do
- Seek emergency veterinary care immediately
- Report what was eaten, the amount, and the time
- Don’t try to induce vomiting without guidance
- The cat may need a blood transfusion in severe cases
Prevention
- Never give table scraps from seasoned human food
- Read labels — many processed foods contain onion or garlic powder
- Be careful with baby food — some contain onion
- Keep onions and garlic out of reach
This article is informational and does not replace a veterinary consultation. In case of emergency, seek veterinary care immediately.