Why it's dangerous
Soluble oxalate salts are absorbed from the gastrointestinal tract and bind with the body's calcium, causing a sudden drop in calcium levels and potential acute renal failure.
Toxic compound: Soluble calcium oxalate crystals
How vets treat it
No treatment plan written for cats was found. For plants with soluble oxalates, the Merck Veterinary Manual describes this care when a pet ate more than a taste or nibble: the vet makes it vomit and gives one dose of activated charcoal with a laxative, then fluids through an IV line for 24 to 48 hours. If blood calcium drops, the vet gives calcium gluconate through the IV. Kidney values are monitored during a hospital stay, and checked if signs develop.
Outlook
No outcome data for cats were found. Merck says exposure to plants with soluble oxalates is not common in pets, but life-threatening signs may occur. It says low blood calcium is not expected after small ingestions and is seen more readily in livestock grazing large amounts of these plants, and that kidney damage is a concern. A Pet Poison Helpline vet notes that dogs and cats are rarely interested in rhubarb because the leaves taste bitter.
Where pets are exposed
- Vegetable gardens. Rhubarb (Rheum rhabarbarum), also called garden rhubarb or pie plant, is a perennial grown for its edible stalks. NC State Extension lists it for vegetable gardens and as an ornamental plant.
- Look for very large leaves, heart-shaped or triangular, on long, thick, reddish stalks, and sometimes small flowers in a dense, elongated cluster.
- Kitchens, when the leaves are cut off fresh stalks before cooking. Pet Poison Helpline says the leaves hold dangerous concentrations of soluble oxalates, and NC State Extension lists the leaves and roots as the most toxic parts.
- Compost bins and heaps. NDSU Extension says rhubarb leaves can be composted like other yard waste.
- Rhubarb pies, jams and purées, which are made from the stalks. Pet Poison Helpline says the stalks contain very little soluble oxalate.
- The main toxins are soluble oxalates (oxalic acid and its salts). NC State Extension and Massey University also list anthraquinone glycosides in the leaves, but none of the sources we checked says what these do in dogs or cats.
Prevention
- Keep your pet away from the leaves in the vegetable garden, for example by fencing off the rhubarb bed. Pet Poison Helpline says the leaves hold dangerous concentrations of soluble oxalates, and NC State Extension also lists the roots among the most toxic parts.
- When you harvest or prepare rhubarb, put the leaves straight into a bin or compost bin your pet can't get into. Don't leave trimmings on the counter, the floor or the garden path.
- If you compost the leaves, keep your pet out of the compost bin or heap. NDSU Extension says the oxalic acid breaks down as the leaves decompose, but still advises keeping children and pets out of compost bins, for many reasons.
- Don't count on the bitter taste. A Pet Poison Helpline vet says dogs and cats are rarely interested in rhubarb because the leaves taste bitter, but Merck says life-threatening signs may occur after exposure to plants with soluble oxalates.
Good to know
The leaves contain the highest concentration of toxins, while the stalks are less prevalent in crystals; it must be differentiated from less toxic insoluble oxalate plants.
Common questions
Is rhubarb toxic to dogs?
Yes. The ASPCA lists rhubarb as toxic to dogs, with soluble calcium oxalates as the toxin and kidney failure, tremors and drooling as signs. The danger is in the leaves: Pet Poison Helpline says they hold dangerous concentrations of soluble oxalates, while the stalks contain very little. Call your vet or a pet poison line if your dog ate any leaves.
Is rhubarb toxic to cats?
Yes. The ASPCA lists rhubarb as toxic to cats, as well as to dogs and horses, with kidney failure, tremors and drooling as signs. No toxic dose or case reports for cats were found. Pet Poison Helpline says the leaves are the part with dangerous concentrations of soluble oxalates. Call your vet or a pet poison line if your cat chewed a leaf.
Which part of rhubarb is poisonous?
The leaves. Pet Poison Helpline says they hold dangerous concentrations of soluble oxalates, and NC State Extension lists the leaves and roots as the most toxic parts. NC State and Massey University also list anthraquinone glycosides in the leaves. A Pet Poison Helpline vet says the stalk contains only very small amounts of oxalates. None of the sources we checked says whether cooking changes how toxic the leaves are, so call your vet if your pet ate leaves, raw or cooked.
Can my dog or cat eat rhubarb stalks or rhubarb pie?
The stalks are not the part the sources warn about. Pet Poison Helpline says the stalks used in rhubarb jams and pies contain very little soluble oxalate and are nontoxic, and the Merck Veterinary Manual says the stalks are edible and not a concern. None of these sources says whether raw stalks differ from cooked ones for pets, and they don't cover the other ingredients of a pie or jam. If your pet ate leaves, or you aren't sure what it ate, call your vet.
How is rhubarb different from houseplants like peace lily?
Both contain oxalates, but of different kinds. Rhubarb contains soluble oxalates, which Merck says can lower blood calcium and may damage the kidneys after large ingestions. Houseplants such as peace lily, philodendron and pothos contain insoluble calcium oxalate crystals, which irritate the mouth and any tissue they touch. Merck says these insoluble crystals don't pose a concern for kidney injury.
My dog or cat chewed a rhubarb leaf. What should I do?
Take away any leftover leaf and call your vet or a pet poison line, even if your pet seems fine. In the US: Pet Poison Helpline (855) 764-7661 or ASPCA Animal Poison Control (888) 426-4435 (both may charge a fee). Don't make your pet vomit or give anything by mouth unless a vet tells you to. Watch for vomiting, drooling, weakness or trembling, and note when it happened and roughly how much was eaten.
Sources
- Merck Veterinary Manual — Houseplants and Ornamentals Toxic to Animals
- ASPCA Animal Poison Control Center — Toxic and Non-toxic Plants: Rhubarb
- ASPCA Animal Poison Control Center — What to Do if Your Pet Is Poisoned (2019)
- Pet Poison Helpline — Rhubarb
- Pet Poison Helpline — Rhubarb Toxicity (Catherine Angle, DVM, 2014)
- NC State Extension — Rheum rhabarbarum (Gardener Plant Toolbox)
- Massey University — Rhubarb (New Zealand poisonous plants database)
- NDSU Extension — Prairie Fare: Be Adventuresome During Rhubarb Season (2018)
- Pet Poison Helpline
This page is informational and is not veterinary advice. If your pet has been exposed to something risky, contact your vet or an animal poison control line right away.
