Leeks are toxic to dogs. They belong to the same plant group as onions and garlic, and the ASPCA lists leek as toxic because of a compound called N-propyl disulfide, which can break down red blood cells. The Merck Veterinary Manual says raw, cooked and concentrated forms of these plants can all cause poisoning.
If your dog ate leek, leek soup or anything seasoned with leek, call your vet or a pet poison line today. The anemia it causes can take several days to show, so a dog who seems normal tonight still needs that call.
Key takeaways
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- Leeks are toxic to dogs in every form: raw, cooked, dried, powdered and in soup.
- They damage red blood cells the same way onion and garlic do.
- Stomach upset can come first; signs of anemia often take several days to appear.
- Small dogs, repeat meals with leek, and Japanese breeds such as Akitas and Shiba Inus face more risk.
- If your dog ate leek, call your vet today. Do not wait for signs.
My dog ate leek: what to do now
- Pick up what is left and put the pot, the bowl or the bag of scraps out of reach.
- Work out the form. A chunk of raw leek, cooked slices, a bowl of leek and potato soup, a spoonful of dried leek or a seasoning mix? Keep the recipe or label.
- Estimate how much and when, and have your dog's weight handy.
- Call your vet, an emergency clinic or a poison line. Pet Poison Helpline's advice is to call or get your dog seen right away if you think they ate something toxic. Early on, the vet has more options.
- Watch your dog for the next week, and call back if anything changes. Signs of red blood cell damage often arrive late.
Go to an emergency vet now if your dog is weak, collapses, has pale or yellow gums, is breathing fast, or passes red or brown urine.
How much leek is a problem?
No one has published a safe or toxic amount of leek for dogs. The best-known figure in this plant group is for raw onion: Merck reports illness in dogs after 15 to 30 grams of raw onion per kilogram of body weight. That number does not transfer neatly to leek, and staying under it does not make any amount safe. Can dogs eat onions? shows what those onion figures look like for different dog sizes.
What raises the risk:
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| What your dog ate | Concern | Why it matters |
|---|---|---|
| What your dog ateA small piece of raw or cooked leek, once, in a large dog | ConcernLower, still worth a call | Why it mattersSmall amount for the body weight, but no amount is known to be safe |
| What your dog ateA bowl of leek soup or leftover leek dish | ConcernModerate | Why it mattersSoup and stews can hold a lot of leek, and often onion or garlic too |
| What your dog ateLeek fed several days in a row | ConcernHigher | Why it mattersMerck says small repeated amounts can cause poisoning as well as one large meal |
| What your dog ateDried leek, leek powder, soup mix or bouillon | ConcernHigher | Why it mattersDrying concentrates the plant, so a spoonful holds a lot of leek |
| What your dog ateAny leek in a small dog or puppy | ConcernHigher | Why it mattersThe same bite is a bigger dose per pound |
| What your dog ateAny leek in an Akita, Shiba Inu or other Japanese breed | ConcernHigher | Why it mattersPet Poison Helpline names these breeds as more sensitive |
Signs of leek poisoning and when they appear
The first signs, when there are any, usually come from the stomach: vomiting, diarrhea, drooling, a sore belly or not wanting to eat.
The damage to red blood cells runs on a slower clock. Merck says blood changes can start within 24 hours, while visible signs of anemia may take several days. Watch for:
- weakness, or tiring out quickly on walks
- pale, grey or yellow gums
- fast breathing, panting at rest, or a racing heart
- red, orange or brown urine
- collapse
A vet can find the blood changes on a test before a dog looks sick. Severe cases may need a hospital stay, oxygen or a blood transfusion.
"My dog has eaten leeks before and was fine"
That can be true. A few bites of leek in a big dog may never cause a visible problem. How a dog does depends on how much leek they ate for their size, whether it was fresh or dried, whether it was one meal or a week of leftovers, and how sensitive that dog is. Anemia from this plant family also shows up days later, so a dog who looked fine at bedtime may have had changes nobody saw. The next exposure is its own event, and it deserves its own call.
Leek soup, powders and related plants
- Leek and potato soup, vichyssoise and stews: often made with onion or garlic and a lot of butter or cream as well. The fat can upset the stomach on its own.
- Vegetable stock, bouillon and soup mixes: frequently contain leek, onion or garlic powder. Check the label before sharing broth.
- Baby food and seasoning blends: some list onion or leek powder. Read the ingredients.
- Elephant garlic: the ASPCA lists it as another name for the same leek species. Treat it like leek.
- Wild leek: the name covers different plants in different regions. If your dog ate a wild plant that smells like onion, bring a photo when you call.
- Onion, garlic, chives, shallots and green onions: the same risk. Can dogs eat garlic? covers garlic in detail.
- Garden beds: the ASPCA's summer garden tips include leeks among garden plants that can be toxic if a pet eats a large amount. Fence off the vegetable patch if your dog digs.
Check what you learned
Quick check
Questions about dogs and leeks
Can dogs eat cooked leeks?
Cooked leek is still toxic. Merck says cooked forms of the onion family can poison dogs too. Cooking does not remove the compounds that harm red blood cells.
My dog ate a small piece of leek. Is it an emergency?
A small piece does not mean your dog will get sick, but there is no amount known to be safe. Call your vet or a poison line with your dog's weight, the amount and the time, and let them decide whether your dog needs to come in.
How long after eating leeks will a dog get sick?
Vomiting or diarrhea can come within the first day. Signs of anemia, such as weakness and pale gums, often take several days.
Is leek broth safe for dogs?
Skip it. Broth made with leek carries the same compounds, and store-bought broth often has onion and garlic too. Plain water or a broth made without any onion-family plants is the safer choice.
Are leeks toxic to cats?
Yes, and cats are more sensitive to the onion family than dogs, according to Merck.
Sources
Checked September 25, 2026.
- ASPCA Animal Poison Control Center, Leek
- Merck Veterinary Manual, Garlic and Onion (Allium spp) Toxicosis in Animals
- Pet Poison Helpline, Leeks
- ASPCA, Our Top Three Summer Garden Safety Tips