Are Onions and Garlic Toxic to Cats?

Onion rings, garlic bread, and even a sprinkle of garlic powder seem harmless — but for cats, the allium family is a serious threat. If you're wondering whether onion and garlic are toxic to cats, the answer is yes, in every form.

The allium family: onions, garlic, leeks, and chives

All alliums contain compounds that damage red blood cells, leading to Heinz body anaemia. Cats are more sensitive than many other pets. Toxicity can build up over several days of small exposures — not just one large meal.

Cooked, raw, or powdered — all are risky

• Raw onion and garlic in salads or dropped scraps
• Cooked onion in sauces, gravies, and takeaway food
• Garlic powder and onion salt in seasonings and stock
• Baby food flavoured with onion or garlic
• Chives and leeks in garden beds

Signs of allium poisoning

Symptoms may take one to five days to appear. Watch for lethargy, pale gums, weakness, reduced appetite, and reddish or brown urine. Blood tests confirm anaemia. Early vet care improves outcomes significantly.

What to do if your cat ate onion or garlic

Call your vet even if your cat seems fine — delayed anaemia is common. Note the form (raw, cooked, powder), amount, and timing. Scan future meals with the Toxic Kitty food scanner before sharing leftovers.