Why is rhubarb toxic to dogs?

Rhubarb contains soluble oxalate salts, concentrated in the leaves. Absorbed oxalates bind calcium in the blood and can form crystals that damage the kidneys — on top of drooling, vomiting and diarrhea from the plant itself.

Are rhubarb stalks as dangerous as the leaves?

The leaves are clearly the worst part, and the stalks people eat contain much less oxalate. But dogs are smaller than we are, "less" is not "none," and there's no established safe amount — so the whole plant stays off-limits.

My dog ate rhubarb crumble. What now?

Cooked stalk in a dessert is a lower-oxalate scenario, but the sugar and butter aren't doing your dog favors either. Watch for vomiting, drooling or lethargy and call your vet if you see them — or if a lot was eaten.

What should I do about rhubarb in my garden?

Fence it off or keep the dog supervised nearby, and bin trimmed leaves securely — wilted leaves tossed on a path or compost heap are exactly what a bored dog samples.

Can Dogs Eat Rhubarb? Vet-Sourced Answer

Can Dogs Eat Rhubarb?

Toxic to dogs

No. Rhubarb — especially the leaves — contains soluble oxalates that can hit a dog's kidneys and nerves. Keep dogs out of the rhubarb patch.

Quick facts

Quick facts
Verdict	Toxic
Risky amount	No safe or toxic dose is established — treat any amount as a risk.
Key symptoms	Drooling, Vomiting, Diarrhea, Lethargy or weakness, Tremors, Changes in thirst or urination (kidney involvement)
What to do	If your dog chewed rhubarb leaves or ate a large amount of the plant, call your vet promptly — soluble oxalates can affect calcium levels and the kidneys, and early treatment protects both.

Why rhubarb earns the toxic label

Rhubarb defends itself with soluble oxalate salts, and the leaves carry the heaviest load — which is why even human cooks discard them. In a dog, chewing the plant irritates the mouth and gut (drooling, vomiting, diarrhea), and absorbed oxalates can bind calcium in the blood and form crystals in the kidneys. Low blood calcium shows up as weakness and tremors; kidney strain shows up as changes in thirst and urination.

The same soluble-oxalate mechanism makes star fruit dangerous, and it’s why high-oxalate greens like spinach sit on the caution list.

Leaves, stalks and desserts

Form	Risk
Leaves (fresh or wilted)	Highest — the classic poisoning
Raw stalks, whole plant	Lower but real — still off-limits
Cooked stalk in desserts	Lowest oxalate, but sugar-heavy — don’t share

Garden access causes most incidents: dogs chew growing plants or scavenge trimmed leaves from paths and compost.

What to do if your dog ate rhubarb

Rinse any plant material out of the mouth if you safely can, then call your vet — especially for leaves or a large raid. Describe what part of the plant and roughly how much. Treatment is straightforward when it starts early: decontamination, fluids to protect the kidneys, and monitoring of calcium levels.

If your dog ate it

If your dog chewed rhubarb leaves or ate a large amount of the plant, call your vet promptly — soluble oxalates can affect calcium levels and the kidneys, and early treatment protects both.

In the US you can also call the ASPCA Animal Poison Control Center at (888) 426-4435 (a consultation fee may apply).

Frequently asked questions

Why is rhubarb toxic to dogs?: Rhubarb contains soluble oxalate salts, concentrated in the leaves. Absorbed oxalates bind calcium in the blood and can form crystals that damage the kidneys — on top of drooling, vomiting and diarrhea from the plant itself.
Are rhubarb stalks as dangerous as the leaves?: The leaves are clearly the worst part, and the stalks people eat contain much less oxalate. But dogs are smaller than we are, "less" is not "none," and there's no established safe amount — so the whole plant stays off-limits.
My dog ate rhubarb crumble. What now?: Cooked stalk in a dessert is a lower-oxalate scenario, but the sugar and butter aren't doing your dog favors either. Watch for vomiting, drooling or lethargy and call your vet if you see them — or if a lot was eaten.
What should I do about rhubarb in my garden?: Fence it off or keep the dog supervised nearby, and bin trimmed leaves securely — wilted leaves tossed on a path or compost heap are exactly what a bored dog samples.