What are the symptoms of Leek poisoning in cats?

vomiting, diarrhea, lethargy, pale gums, weakness

Leek

Q: Can cats eat Leek?

Dangerous: Never — allium family, highly toxic to cats. Leeks are allium vegetables that contain thiosulfates and organosulfur compounds highly harmful to cats' red blood cells. The entire plant is toxic, including the bulb and green leaves. Cats are particularly vulnerable to allium toxicity due to their limited G6PD enzyme levels. Leeks are frequently used in cooking, so be aware of soups, stews, and casseroles that may contain them. Source: ASPCA.

Dangerous

Verdict

Never — allium family, highly toxic to cats.

Toxic principle: thiosulfate

Source: ASPCA · Verified 2026-06-12

If your cat ate this

Cats hide symptoms — don't wait and see. Even small amounts of certain substances can be fatal to a cat. Act fast.

1. Call your veterinarian immediately
US — National hotline: ASPCA Animal Poison Control Center (888) 426-4435 aspca.org(24/7, Consultation fee may apply.)
US — National hotline: Pet Poison Helpline (855) 764-7661 petpoisonhelpline.com(24/7, $89 per incident fee; also covers Canada.)
GB — National hotline: Animal PoisonLine 01202 509 000 animalpoisonline.co.uk(24/7, £35 per call (8am–8pm weekdays), £45 at other times.)
AU — National hotline: Animal Poisons Helpline 1300 869 738 animalpoisons.com.au(24/7)
NZ — National hotline: Animal Poisons Helpline 0800 869 738 poisons.co.nz(11am–7pm NZ time (currently being extended), Charges apply.)
CA — National hotline: Pet Poison Helpline (855) 764-7661 petpoisonhelpline.com(24/7, $89 per incident fee.)

Verified 2026-08-06

Verdict

Leeks are allium vegetables that contain thiosulfates and organosulfur compounds highly harmful to cats' red blood cells. The entire plant is toxic, including the bulb and green leaves. Cats are particularly vulnerable to allium toxicity due to their limited G6PD enzyme levels. Leeks are frequently used in cooking, so be aware of soups, stews, and casseroles that may contain them.