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Toxic to dogs. The ASPCA lists leek as toxic to dogs. Same serious family tier as onion and garlic. The anemia is delayed, so a dog that ate a bowl of leek soup can look merely tired while red cells are breaking down. Call the same day, every time.
Leeks are the mild mannered Allium of winter cooking, braised, souped and roasted through the cold months, and their green tops wave from vegetable beds all summer. Owners who have absorbed the onion warning often give leeks a pass as the gentler cousin. The ASPCA lists leek as toxic to dogs with the identical principle and sign list as onion and garlic, because botanically the gentleness is a flavor note, not a chemistry one.
In the bed, leeks grow as thick white shanks topped with fountains of flat blue green leaves, far stouter than onion or chive tops. In the kitchen, look for them in the forms dogs steal: potato leek soup, braised leeks in a roasting pan, and trimmings in the compost caddy.
The ASPCA names the toxic principle of leek as N-propyl disulfide. Leek is an Allium, and it carries the family's red blood cell toxin, N-propyl disulfide. The compound damages red cells from within, producing the Heinz body form of anemia: cells weaken, rupture, and the dog becomes weak, fast hearted and short of breath over the following days. The ASPCA entry for leek carries the additional common name elephant garlic, a quirk worth knowing, because it means two pantry names point at this one listing.
The clinical signs the ASPCA lists for leek are: vomiting, breakdown of red blood cells (hemolytic anemia, Heinz body anemia), blood in the urine, weakness, a high heart rate and panting. Soup is the classic leek poisoning route: a dog that counter surfs a pot or bowl of soup eats leek cooked soft in fat and stock, in a volume no dog would ever take from the raw plant. Garden cases happen at harvest, when pulled leeks and trimmings sit in a basket at ground level. Either way, the timeline deceives: vomiting may come early, but the weakness, panting and dark urine of anemia build over days, and the history has to reach back to the meal.
Most dangerous part: The bulb and thick white stem base hold the most compound per bite, and cooked leek in soups and leftovers is the form dogs actually consume in quantity.
The elephant garlic name on this entry causes genuine confusion, because elephant garlic in shops is indeed this species grown for giant mild cloves, while true garlic has its own page here. For a dog, the distinction changes nothing: both Allium entries carry the same principle and the same advice. Treat every Allium in the kitchen, bulb, stem, top or powder, as one rule.
Call your veterinarian, the ASPCA Animal Poison Control Center on (888) 426-4435, or the Pet Poison Helpline on (855) 764-7661 right away, even if your dog looks fine. Some poisons take hours or days to show their worst effects. Do not make your dog vomit unless a veterinarian tells you to, and keep the packaging, a photo, or a sample of what was eaten to show the clinic.
Keep leek trimmings and soup leftovers in closed bins, never in an open compost caddy, and fence vegetable beds where leeks are growing if your dog digs or grazes. When a soup pot cools on the stove, a lid on it is a dog safety device, not just a kitchen habit.
For the vegetable bed, plenty of dog safer crops exist outside the Allium row; the ASPCA lists plants such as garden marigold as non-toxic companions for beds. The practical swap is layout: keep the whole Allium block, onions, garlic, leeks and chives, in one fenced section you can manage as a unit. Whatever you plant next, check it on the toxic plants index approach: confirm the plant on the ASPCA toxic and non-toxic list under its scientific name, Allium ampeloprasum is the name to avoid here, before it goes in the ground or on the shelf.
Yes. The ASPCA lists leek (Allium ampeloprasum) as toxic to dogs. Its toxic principle is N-propyl disulfide, and the signs it lists include vomiting, breakdown of red blood cells (hemolytic anemia, Heinz body anemia), blood in the urine, weakness, a high heart rate and panting.
Call your veterinarian, the ASPCA Animal Poison Control Center on (888) 426-4435, or the Pet Poison Helpline on (855) 764-7661 straight away. Note what part of the plant was eaten and roughly how much, keep any remaining plant material to show the clinic, and do not make your dog vomit unless a veterinarian tells you to.
The bulb and thick white stem base hold the most compound per bite, and cooked leek in soups and leftovers is the form dogs actually consume in quantity.
No. The ASPCA gives leek the same toxic principle and the same clinical sign list as onion, including red blood cell breakdown. Milder flavor does not mean milder toxicology in this family.
Yes, that delayed pattern fits Allium anemia: weakness, panting and a fast heart rate as red cells break down. Contact your veterinarian promptly and name the soup and the day it was eaten.
This page is general information drawn from the published guidance of the organizations listed under Sources below. It is not veterinary advice, and it does not replace your own veterinarian, who knows your dog. If your dog has eaten something toxic, contact your veterinarian, the ASPCA Animal Poison Control Center on (888) 426-4435, or the Pet Poison Helpline on (855) 764-7661 straight away. A consultation fee may apply on the helplines.
Last updated: November 2026. Every verdict on this page was checked against the sources listed above. How we work: our methodology.
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