Pet safety
Is Welsh Oniontoxic to cats & dogs?
Allium fistulosum
Quick verdict — at a glance
- Toxic to cats?
- Yes — toxic
- Toxic to dogs?
- Yes — toxic
- ASPCA classification
- Toxic to pets · botanical name Allium fistulosum
Is welsh onion safe for cats and dogs?
Toxic — the ASPCA lists welsh onion as a clear no for cats and dogs. The painful part for the pet is usually quick and intense; the right move is to keep it out of any room a pet roams unsupervised. This classification follows the ASPCA Toxic and Non-Toxic Plant List, the most widely used reference for companion-animal plant safety in the US and the standard most UK vets cite as well. ASPCA-listed as toxic to cats, dogs and horses. Like all Allium species it contains organosulfur compounds (e.g. N-propyl disulfide) that cause oxidative damage to red blood cells, leading to Heinz-body haemolytic anaemia; signs include vomiting, lethargy, pale gums, rapid breathing and red-tinged urine. Cats are especially sensitive. Keep all parts away from pets.
| Pet | Toxic? | Per ASPCA |
|---|---|---|
| Cats | Yes | Toxic to pets |
| Dogs | Yes | Toxic to pets |
What happens if a pet eats welsh onion?
ASPCA-listed as toxic to cats, dogs and horses. Like all Allium species it contains organosulfur compounds (e.g. N-propyl disulfide) that cause oxidative damage to red blood cells, leading to Heinz-body haemolytic anaemia; signs include vomiting, lethargy, pale gums, rapid breathing and red-tinged urine. Cats are especially sensitive. Keep all parts away from pets. Signs usually appear soon after chewing rather than hours later. If you see drooling, pawing at the mouth, head-shaking, vomiting, loss of appetite, or unusual lethargy after your pet has had access to welsh onion, treat it as a suspected ingestion and act on the steps below.
What to do if your pet ate welsh onion
- Remove any plant material from your pet's mouth and move welsh onion out of reach.
- Note how much was eaten and when, and watch for drooling, vomiting, or lethargy.
- Do not induce vomiting unless a vet or poison-control specialist instructs you to.
- Call your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 and follow their advice.
- Bring a leaf or photo of welsh onion to the appointment so it can be treated correctly.
This page is general guidance, not veterinary advice. Pets vary, and a reaction may be to soil, fertiliser, or pesticide rather than the plant. If you are worried, always contact a vet or the ASPCA Animal Poison Control Center on (888) 426-4435 — do not wait for symptoms to worsen.
Pet-safe alternatives to welsh onion
Want the same look without the risk? These plants are listed as non-toxic to cats and dogs by the ASPCA and have similar care needs:
- Cucumber — non-toxic to cats and dogs (care guide)
- Lettuce — non-toxic to cats and dogs (care guide)
- Bean — non-toxic to cats and dogs (care guide)
- Pea — non-toxic to cats and dogs (care guide)
Welsh Onion and pets — frequently asked questions
Is welsh onion toxic to cats?
Welsh Onion (Allium fistulosum) is toxic to cats according to the ASPCA. ASPCA-listed as toxic to cats, dogs and horses. Like all Allium species it contains organosulfur compounds (e.g. N-propyl disulfide) that cause oxidative damage to red blood cells, leading to Heinz-body haemolytic anaemia; signs include vomiting, lethargy, pale gums, rapid breathing and red-tinged urine. Cats are especially sensitive. Keep all parts away from pets. Keep it out of reach and contact your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 if your cat chews it.
Is welsh onion toxic to dogs?
Per the ASPCA, Welsh Onion (Allium fistulosum) is toxic to dogs. Dogs often chew more enthusiastically than cats, so a toxic plant like welsh onion is best removed from the floor and low shelves entirely.
What happens if my pet eats welsh onion?
ASPCA-listed as toxic to cats, dogs and horses. Like all Allium species it contains organosulfur compounds (e.g. N-propyl disulfide) that cause oxidative damage to red blood cells, leading to Heinz-body haemolytic anaemia; signs include vomiting, lethargy, pale gums, rapid breathing and red-tinged urine. Cats are especially sensitive. Keep all parts away from pets. Signs usually appear soon after chewing rather than hours later. If you see drooling, pawing at the mouth, head-shaking, vomiting, loss of appetite, or unusual lethargy after your pet has had access to welsh onion, treat it as a suspected ingestion and act on the steps below.
What should I do if my cat or dog ate welsh onion?
Stay calm. Remove any remaining plant material from your pet's mouth and take the plant away so they cannot eat more. Note roughly how much was eaten and when. Do not make your pet vomit unless a vet or poison-control specialist tells you to. Call your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 (a consultation fee may apply) and follow their advice. Bringing a photo or a leaf of welsh onion to the appointment helps the vet treat it correctly.
What are pet-safe alternatives to welsh onion?
If you want a similar look without the risk, good non-toxic swaps include cucumber, lettuce, bean, pea. All of these are listed as non-toxic to cats and dogs by the ASPCA, so they suit a home where pets have access to your plants.
Full welsh onion care
Pet-safety is one piece of the picture. For light, watering, soil, and troubleshooting, see the complete welsh onion care guide, or browse the full pet-safe plant library to check another plant before you buy it.