What should I do if my cat ate Onion?

Remove any remaining onion or onion-containing food, then call ASPCA Poison Control or your vet for guidance. Do not induce vomiting at home — Pet Poison Helpline cautions that unsupervised home emesis is one of the most common pet-poisoning first-aid mistakes. Call your vet or ASPCA Poison Control (888-426-4435) any time you suspect ingestion — even a small bite. Concentrated forms (onion powder, dehydrated flakes, dry soup mixes) are especially dangerous and warrant an immediate call.

What should I do if my dog ate Onion?

Remove any remaining onion or onion-containing food and call your vet or poison control for guidance. Do not induce vomiting at home unless directed — Pet Poison Helpline lists unsupervised home emesis as a common, dangerous first-aid mistake. Call your vet or ASPCA Poison Control (888-426-4435) for any known ingestion of onion, onion powder, or onion-containing prepared foods (taco seasoning, soup mixes, baby food). Symptoms may not appear right away, so don't wait for them.

Onion — (c) Wuyongzheng, some rights reserved (CC BY) — Photo by (c) Wuyongzheng, some rights reserved (CC BY)iNaturalistCC BY

Photo by (c) Wuyongzheng, some rights reserved (CC BY)iNaturalistCC BY

Pet safety reference

Onion

Q: Is Onion safe for cats?

Onion is potentially toxic to cats. Ingestion can cause oxidative damage to red blood cells, leading to hemolytic anemia. Please contact your veterinarian or an animal poison control center immediately if ingestion is suspected.

Q: Is Onion safe for dogs?

Onion is potentially toxic to dogs. Onions contain N-propyl disulfide, which can cause Heinz body anemia in dogs. Immediate veterinary attention is required if your dog has consumed onion in any form.

Allium cepa

The onion is a bulbous vegetable widely used in cooking that contains compounds capable of damaging red blood cells in pets. Ingestion of any part of the plant, including the bulb, can lead to serious health complications.

Check a list

Allium cepaBulb OnionGarden OnionOnion

Light: Full sun
Habit: Bulbous herb
Care: Moderate

Safety status

Cats & Dogs

Potentially toxic

Consulted references classify the plant as toxic or irritating for that pet type.

Verified against ASPCA/provenance audit 2026-05-06 on May 6, 2026.

Sources

ASPCA Toxic Plant List

If a pet has chewed or swallowed plant material and is showing symptoms, contact a veterinarian or poison resource immediately. This product is for structured reference, not diagnosis.

Cats — concern notes

Common signs

Vomiting, diarrhea, lethargy, pale gums, and rapid breathing.

Escalation note

Ingestion can cause oxidative damage to red blood cells, leading to hemolytic anemia. Please contact your veterinarian or an animal poison control center immediately if ingestion is suspected.

Dogs — concern notes

Common signs

Weakness, decreased appetite, abdominal pain, and discolored urine.

Escalation note

Onions contain N-propyl disulfide, which can cause Heinz body anemia in dogs. Immediate veterinary attention is required if your dog has consumed onion in any form.

Safer alternatives

No hand-picked alternatives for this plant yet. You can still pick your own using the Compare button on any other plant.

Source evidence

ASPCA Toxic Plant List

toxicology · 99% reliability

Open source

Onion is toxic to both cats and dogs, causing damage to red blood cells.

NC State Extension Plant Toolbox

botanical · 94% reliability

Open source

Allium cepa is a biennial herb grown as an annual for its edible bulb.

cats safety page My cat ate Onion dogs safety page My dog ate Onion

Often compared with

Commonly confused with

Same Allium genus.

Leek

Allium ampeloprasum

Leeks are members of the onion family that contain compounds capable of damaging red blood cells in pets. Ingestion of any part of the plant can lead to gastrointestinal upset and potential anemia.

Potentially toxic for cats & dogs.

Same safety verdict

Other plants with the same verdict

Monstera

Monstera deliciosa

Monstera deliciosa is a popular tropical houseplant known for its large, fenestrated leaves and vining growth habit. It contains insoluble calcium oxalate crystals that can cause irritation if ingested by pets.

Potentially toxic for cats & dogs.

Snake Plant

Dracaena trifasciata

Dracaena trifasciata is a popular, hardy houseplant known for its stiff, sword-like leaves with striking yellow margins. It is widely appreciated for its air-purifying qualities and ability to thrive in various indoor conditions.

Potentially toxic for cats & dogs.

Philodendron

Philodendron spp.

Philodendrons are popular tropical foliage plants known for their lush, heart-shaped or split leaves. They contain insoluble calcium oxalate crystals that can cause irritation if ingested.

Potentially toxic for cats & dogs.

Peace Lily

Spathiphyllum

The Mauna Loa Peace Lily is a popular indoor plant known for its elegant white spathes and lush foliage. It contains insoluble calcium oxalate crystals that can cause irritation upon contact or ingestion.

Potentially toxic for cats & dogs.

Same growing conditions

Plants for the same room

Strawberry

Fragaria spp.

Strawberry plants are popular garden and container fruits known for their edible berries and trifoliate leaves. They are considered non-toxic to pets, though ingestion of large amounts of plant material may cause minor digestive discomfort.

Generally safe for cats & dogs.

Carrot

Daucus carota var. sativa

The carrot is a popular root vegetable often grown in home gardens, known for its edible taproot and feathery foliage. It is considered safe for pets, though large ingestions of fibrous plant material may occasionally cause minor digestive upset.

Generally safe for cats & dogs.

Dill

Anethum graveolens

Dill is a popular culinary herb known for its feathery, aromatic foliage and is generally considered safe for household pets. While non-toxic, consuming large amounts of the fibrous plant material may occasionally cause mild digestive upset in some animals.

Generally safe for cats & dogs.

Moss Campion

Silene acaulis

Moss Campion is a low-growing, cushion-forming perennial wildflower native to alpine regions. It is considered non-toxic to pets, though ingestion of large amounts of plant material may cause minor digestive upset.

Uncertain for cats & dogs.