Can Cats Eat Onion?
No — onion is even more dangerous for cats than for dogs. Feline red blood cells are especially sensitive to its sulfur compounds; small and repeated exposures can cause anemia.
Last reviewed: July 24, 2026
Why is it dangerous?
Cats are among the pets most sensitive to allium-induced red-cell damage. Raw, cooked, roasted, or powdered — all forms cause the same harm. Cats rarely eat onion directly; the risk comes from bread soaked in broth, leftovers from onion dishes, and instant soups or purees that may contain onion powder. That is why reading labels matters.
What to do if your cat ate onion
Note what the dish contained and roughly how much was eaten, then call your veterinarian. Symptoms can surface days later; if you see lethargy, pale gums, or dark urine, go to the clinic without waiting.
Watch for these signs
- Lethargy, no interest in play
- Pale gums
- Loss of appetite, vomiting
- Dark urine
- Rapid breathing
If you notice any of these, contact a veterinarian without waiting.
Frequently asked questions
Is bread or rice soaked in broth safe to share?
No — commercial broths and pan juices usually contain onion or onion powder. Sharing them with a cat is a hidden onion source.
How much onion is a problem for a cat?
There is no proven safe threshold; cats are small and highly sensitive, so even small amounts should be taken seriously and repeated exposure prevented.
Related answers
Sources
This guide is based on publications from the following veterinary bodies. Where sources differ, we take the more cautious position; the final decision is always your veterinarian's.