That rhubarb plant in your garden looks harmless. It is not.
Rhubarb and dogs are a bad combination, mostly because of the leaves. The plant contains soluble oxalates (oxalic acid and its salts), which can lower blood calcium and, after a large enough dose, damage the kidneys.
Most owners do not know which parts are dangerous, how quickly symptoms develop, or when to call a vet versus wait and watch.
This article covers exactly that: the toxic compounds involved, symptoms of rhubarb poisoning in dogs, how vets treat it, and what recovery actually looks like.
Is Rhubarb Toxic to Dogs?
Rhubarb is toxic to dogs. The ASPCA Animal Poison Control Center lists rhubarb as toxic to dogs, cats, and horses, with soluble calcium oxalates as the toxic principle and kidney failure, tremors, and salivation as the clinical signs.
The toxicity affects dogs of all breeds and sizes. Smaller dogs reach a dangerous oxalate dose with less plant material than larger dogs, but no dog is immune to the effects of eating rhubarb leaves.
The danger is concentrated in the leaves. Veterinary toxicology references treat the stalks, the part people bake into pies, as low risk, but that does not make them a recommended food for dogs. More on that difference below.
In 2024, the ASPCA Animal Poison Control Center responded to more than 451,000 calls related to toxic exposures in animals, a nearly 4% increase from the year before. Plants and fungi together accounted for 8.1% of all exposures, ranking 6th on the ASPCA’s top 10 toxins of 2024.
I grow vegetables in my yard, and rhubarb used to be one of them. The first time I had a dog sniff around the rhubarb stalks, I pulled the whole plant. Not worth the risk.
Why the Entire Plant Is a Problem
Rheum rhabarbarum contains oxalates throughout the plant, but the soluble oxalate that causes poisoning is concentrated in the large triangular leaves.
- Leaves: the highest concentration of soluble oxalate and the part responsible for poisoning cases
- Stalks: lower risk, but not oxalate-free
- Roots: also contain oxalate and other irritating compounds
Cooking rhubarb reduces oxalate but does not remove it. A dog that eats rhubarb pie is mainly eating stalks, so the bigger problem is usually the sugar and fat in the filling and crust, which can cause gastrointestinal upset.
Which Dogs Face the Highest Risk
Small breeds already carry a predisposition to calcium oxalate stone formation. A 2019 analysis of more than 124,000 calcium oxalate stones submitted to the University of Minnesota’s Minnesota Urolith Center found that all 12 high-risk breeds were small breeds, with Miniature Schnauzers and Bichon Frises showing about 12 times the odds of stone formation compared with breed registry data (Hunprasit et al., Journal of Veterinary Internal Medicine, 2019).
Other high-risk breeds in that study include the Lhasa Apso, Pomeranian, Yorkshire Terrier, and Maltese, and earlier Minnesota research also flagged the Shih Tzu and Miniature and Toy Poodles (Lekcharoensuk et al., JAVMA, 2000). For these dogs, extra dietary oxalate from any source, including rhubarb, adds to an existing vulnerability.
Dogs with pre-existing kidney conditions or chronic dehydration are also more likely to suffer kidney injury from an oxalate exposure.
What Makes Rhubarb Dangerous to Dogs?
Rhubarb contains 2 classes of compounds that matter for dogs: soluble oxalate salts (including oxalic acid) and anthraquinones. Both cause harm, but through different mechanisms.
| Compound | Location in Plant | Primary Effect |
|---|---|---|
| Oxalic acid / soluble oxalates | Leaves (high concentration), stalks (lower risk) | Calcium depletion and kidney crystal formation |
| Anthraquinones (such as emodin) | Leaves and roots | Gastrointestinal irritation and laxative effects |
| Sour, acidic taste and plant irritants | Leaves and stalks | Drooling and mouth irritation, which often stop a dog after a bite or two |
Oxalic Acid and Calcium Oxalate Crystal Formation
When a dog eats rhubarb leaves, the soluble oxalates are absorbed from the gut into the bloodstream. Soluble forms are absorbed far more readily than insoluble ones, which is why they cause systemic effects.
Once in the blood, oxalate binds with free calcium. This does 2 things at once: it removes calcium from circulation, causing hypocalcemia, and it forms calcium oxalate crystals that can precipitate in the kidney tubules.
Crystal accumulation in the renal tubules damages the tubule cells, impairing the kidney’s ability to filter waste. This is how a large rhubarb leaf ingestion can progress to acute kidney injury in dogs, as described in the Merck Veterinary Manual’s section on soluble oxalate plants.
Oxalate levels in rhubarb vary a lot by cultivar, season, and growing conditions. Food analyses compiled in a 2023 review list roughly 990 to 1,235 mg of total oxalate per 100 grams of raw rhubarb stalk, with only about 30% of it in the soluble form the body absorbs readily (Salgado et al., Foods, 2023). The leaves are the part that carries a dangerous load of the soluble form.
Anthraquinones in Rhubarb Leaves
Anthraquinones such as emodin are compounds rhubarb is known for, and they are the reason rhubarb root has a long history as a laxative. A 2025 review found emodin levels in rhubarb leaves roughly 5 times higher than in the roots (Wang et al., Food Science and Biotechnology, 2025). They irritate the gastrointestinal tract, which can add to vomiting and diarrhea independent of the oxalate pathway.
That means a dog can develop GI symptoms before kidney problems show up in bloodwork. Early vomiting sometimes brings plant material back up, reducing total oxalate absorption.
The problem is that many pet owners see the GI symptoms pass and assume their dog is recovering, when calcium and kidney effects may still be developing.
Are Rhubarb Leaves More Toxic Than Stalks to Dogs?
Yes. The leaves are the toxic part of rhubarb. They carry the high levels of soluble oxalate that cause poisoning, while stalk oxalate content varies by cultivar and growing conditions and is far less of a concern.
Pet Poison Helpline states that rhubarb stalks “contain very little soluble oxalate and are nontoxic”, and the Merck Veterinary Manual likewise notes that rhubarb stalks are edible and not a concern. The tart flavor also tends to stop dogs from eating much.
So how do those statements fit with the advice not to feed rhubarb? Nontoxic does not mean good for dogs. A bite of stalk is very unlikely to poison a dog, but stalks offer no nutritional benefit, can still upset the stomach, and usually come with sugar when cooked. The leaves are the real emergency. The stalks are simply not a food worth sharing.
Cooked vs. Raw Rhubarb Toxicity
Cooking does not make rhubarb leaves safe for dogs. Boiling leaches some oxalate into the cooking water, but it does not eliminate it.
- Raw rhubarb leaf: the most concentrated source of soluble oxalate in the plant (highest risk)
- Cooked rhubarb stalk: low risk; in one analysis, boiling cut the soluble oxalate in stalks from about 287 to 81 mg per 100 grams (Salgado et al., 2023), but it is still not a recommended food
- Rhubarb pie filling or jam: low oxalate risk, but the sugar and fat cause separate GI issues
Stalk color is not a safety indicator. Green-stalked and red-stalked varieties of Rheum rhabarbarum are the same species, and the leaves of both are toxic.
Ornamental Rhubarb and Other Rheum Species
Ornamental rhubarb (Rheum palmatum and related species) is a close relative used in garden landscaping. Treat any Rheum species in your garden with the same caution as edible garden rhubarb.
The species distinction matters to gardeners choosing plants, not to a dog that chews the nearest large leaf it finds.
What Are the Symptoms of Rhubarb Poisoning in Dogs?
Rhubarb poisoning produces symptoms in 2 stages. The first wave targets the mouth and digestive tract. The second involves calcium and kidney effects that develop over hours to days.
Early-Onset Symptoms (0 to 2 Hours)
Rhubarb leaves are sour and irritating to chew, so many dogs stop after a bite or two. That is one reason serious poisoning is uncommon: according to the Merck Veterinary Manual, a taste or nibble usually causes only GI upset such as vomiting and loss of appetite.
Early signs include:
- Excessive drooling (often the first visible sign)
- Pawing at the mouth or rubbing the face on the ground
- Vomiting, sometimes containing plant material
- Diarrhea
- Loss of appetite
- Lethargy or restlessness
A dog that gulps pieces of leaf without much chewing may show fewer mouth signs, so the first clue can be vomiting a little later.
Delayed Kidney and Systemic Symptoms
After a larger ingestion, signs of low blood calcium and kidney injury can follow. These symptoms signal that the poisoning has progressed beyond the GI tract.
Signs of calcium and kidney involvement:
- Increased thirst and urination, then decreased urination as function drops
- Lethargy, vomiting, and loss of appetite that return or worsen
- Abdominal pain and tenderness
- Muscle weakness, wobbliness, and tremors (from hypocalcemia)
- Seizures or collapse in severe cases
The ASPCA lists kidney failure, tremors, and salivation as the clinical signs for rhubarb toxicity. Neurological symptoms appear when serum calcium drops far enough to disrupt nerve and muscle function.
How Much Rhubarb Is Dangerous for a Dog?
There is no established safe dose of rhubarb for dogs, and no published toxic dose specific to dogs. Any rhubarb leaf ingestion warrants a call to a vet or poison control. The ASPCA advises calling its Animal Poison Control Center at (888) 426-4435 or your vet right away if you think your pet ate something toxic.
What the veterinary literature does describe is a sliding scale. A taste or nibble usually causes only GI upset, while larger ingestions can drop blood calcium and injure the kidneys. Because owners rarely know exactly how much was eaten, the dog’s size is the best rough guide to urgency.
| Dog Weight | Risk Level After Leaf Ingestion | Action |
|---|---|---|
| Under 5 kg (toy breeds) | High: even partial leaf consumption can be significant | Contact a veterinarian immediately |
| 5–15 kg (small breeds) | Moderate to high | Contact a veterinarian immediately |
| Over 15 kg (medium and large breeds) | Lower risk per bite, but still unsafe | Veterinary consultation recommended |
Cumulative Exposure Risk
Repeated small exposures are worth taking seriously. A dog that nibbles rhubarb leaves in the garden over days or weeks may never eat enough at once to show acute symptoms, but each exposure adds oxalate the kidneys have to clear.
This is especially relevant for dogs with unsupervised access to gardens where rhubarb grows alongside other plants.
Rhubarb, spinach, and beets are among the common high-oxalate foods (Noonan and Savage, Asia Pacific Journal of Clinical Nutrition, 1999). For a dog that already gets high-oxalate foods regularly, or a breed prone to calcium oxalate stones, garden nibbling adds to the total load.
Small and Toy Breed Vulnerability
Small breed dogs face 2 separate risks: they reach a harmful oxalate dose with less plant material, and they already have a higher baseline predisposition to calcium oxalate stone formation.
The Minnesota Urolith Center analysis found that breeds like the Miniature Schnauzer had about 8 times the odds of calcium oxalate stones compared with the general veterinary hospital population, and about 12 times the odds compared with breed registry data. Adding dietary oxalate from rhubarb exposure does that risk profile no favors.
Toy and small breeds including the Yorkshire Terrier, Pomeranian, Lhasa Apso, and Shih Tzu are consistently overrepresented in calcium oxalate urolithiasis studies. For these dogs, any rhubarb exposure is a higher-stakes event than it would be for a large mixed-breed dog.
What to Do If a Dog Eats Rhubarb
Act immediately. Do not wait for symptoms to appear before contacting a vet. Calcium and kidney effects can develop before obvious signs show, and early decontamination and fluids give the kidneys the best chance.
Immediate Steps
Call first, move second. Contact the ASPCA Animal Poison Control Center at (888) 426-4435 or your nearest emergency vet before doing anything else. The ASPCA APCC operates 24 hours a day, 365 days a year (a consultation fee applies).
Gather this information before the call:
- Dog’s weight, age, breed, and any existing health conditions
- Which part of the rhubarb plant was consumed (leaf vs. stalk)
- Estimated quantity, described specifically (“half a leaf the size of my hand” is more useful than “some rhubarb”)
- Time of ingestion
- Current symptoms, if any
Take photos of the plant and bring a sample or bagged piece to the veterinary clinic if possible. This helps confirm the species and rules out other toxic plants in the garden.
What Not to Do
Do not induce vomiting without direct veterinary instruction. Inducing vomiting is sometimes appropriate and sometimes contraindicated depending on the dog’s condition, time elapsed, and what was consumed. Getting this wrong can cause additional harm.
There is no effective home treatment for rhubarb leaf poisoning. If more than a nibble was eaten, the right care setting is a veterinary clinic.
How Do Vets Treat Rhubarb Poisoning in Dogs?
Treatment intensity depends on how much was ingested, which plant part, how quickly the dog reached the clinic, and what symptoms are present at admission.
There is no specific antidote for oxalate toxicity. Dogs that ate more than a taste of leaf usually need hospital care, since the Merck Veterinary Manual recommends 24 to 48 hours of IV fluids for these exposures. Treatment is supportive and focused on decontamination, calcium restoration, and kidney protection.
Decontamination Protocol
If the dog arrives soon after ingestion and shows no contraindications, the vet will typically induce emesis to remove plant material from the stomach before further absorption occurs.
Activated charcoal is typically given as a single dose after emesis, along with a cathartic, to bind what remains in the gastrointestinal tract and limit absorption. This step is time-sensitive. The longer the gap between ingestion and treatment, the less effective decontamination becomes.
In cases where the dog swallowed large pieces of leaf, gastric lavage may be considered instead of or alongside emesis induction.
Kidney Support and Calcium Correction
IV fluid therapy is the backbone of treatment. Fluids help flush calcium oxalate crystals from the renal tubules, correct dehydration, and maintain kidney perfusion while the organ recovers.
Key treatment components:
- IV calcium gluconate when bloodwork shows hypocalcemia, to restore serum calcium to the normal range
- Blood urea nitrogen (BUN) and creatinine panels to monitor kidney function during hospitalization
- Urinalysis to check for calcium oxalate crystals in urine and measure output
- Anti-seizure medication if neurological signs are present
A complete blood count, biochemistry profile, and urinalysis are standard on admission. These confirm the extent of kidney involvement and rule out concurrent conditions that might complicate treatment.
VCA Animal Hospitals notes that the initial prognosis for acute kidney injury in dogs is guarded, with a mortality rate of approximately 60% when all causes of AKI are counted together. Dogs treated early for plant-based oxalate exposure, before significant kidney injury sets in, generally have better outcomes than this aggregate figure suggests.
Can Dogs Recover Fully From Rhubarb Poisoning?
Most dogs treated quickly do recover. Two things matter most: how much leaf was eaten and how fast treatment started.
Early decontamination and fluids are what keep a rhubarb exposure from turning into kidney injury, which is why poison control services advise calling before symptoms appear.
What Recovery Actually Looks Like
Prognosis after a small nibble is generally good. Most dogs that chewed only a small amount before the taste stopped them have nothing more than a bout of GI upset.
For dogs with confirmed kidney involvement, a 2022 study in the Journal of Veterinary Internal Medicine tracked 132 dogs recovering from acute kidney injury across all causes. Serum creatinine normalized in 75% of dogs either at discharge or during follow-up, with an estimated median survival time of 1,322 days (Bar-Nathan et al., Journal of Veterinary Internal Medicine, 2022).
The study found that the cause of the AKI mattered more to long-term outcome than the severity of kidney dysfunction at its peak. In that dataset, all 7 dogs with nephrotoxic (toxin-caused) injury, mostly from NSAID overdoses, had their creatinine normalize, though that group was small.
When Full Recovery Is Less Likely
Delayed treatment sharply changes outcomes. The longer oxalate goes untreated, the more time crystals have to deposit in the renal tubules.
3 factors push recovery outcomes in the wrong direction:
- Pre-existing kidney disease or chronic dehydration at the time of ingestion
- Large-quantity leaf ingestion, especially in dogs under 10 kg
- Treatment starting many hours after ingestion
Dogs that develop anuria (complete failure to produce urine) during hospitalization face a significantly worse prognosis. In a companion 2022 study of 249 hospitalized dogs with AKI, the case fatality rate was 50% in dogs with anuria compared with 28% in dogs without it (Rimer et al., Journal of Veterinary Internal Medicine, 2022).
Post-Recovery Monitoring
Follow-up blood panels in the days and weeks after discharge confirm whether kidney function is trending back toward normal ranges.
BUN and creatinine are the two key markers. If creatinine stays elevated at follow-up rechecks instead of normalizing, the dog has likely progressed to azotemic chronic kidney disease (CKD), which requires long-term dietary and fluid management. In the Bar-Nathan study, creatinine normalized in 55% of dogs by discharge and in another 20% during follow-up.
Dogs that recover fully from a single rhubarb exposure and have no pre-existing conditions generally do well long term. Ask your vet whether any follow-up kidney checks are needed, and keep the dog away from the plant.
What Other Plants Contain Oxalates That Are Toxic to Dogs?
Rhubarb belongs to a broader category of oxalate-containing plants that create similar risks for dogs. Understanding which plants share this toxicity mechanism helps owners make better decisions for indoor and outdoor spaces.
Soluble oxalates (like those in rhubarb) differ from insoluble oxalate plants in one key way: soluble forms absorb systemically and can cause kidney injury, while insoluble forms primarily cause local oral irritation (Merck Veterinary Manual).
| Plant | Oxalate Type | Primary Risk to Dogs | Location |
|---|---|---|---|
| Rhubarb (Rheum rhabarbarum) | Soluble | Kidney injury, hypocalcemia | Garden |
| Star fruit (carambola) | Soluble | Hypocalcemia and kidney injury | Kitchen/fruit bowl |
| Shamrock (Oxalis spp.) | Soluble | Kidney and gastrointestinal damage | Indoor/outdoor |
| Dieffenbachia | Insoluble | Oral pain and airway swelling | Houseplant |
| Philodendron | Insoluble | Oral irritation and vomiting | Houseplant |
Soluble Oxalate Plants: The Higher-Risk Group
Soluble oxalate plants share rhubarb’s mechanism of systemic calcium binding and kidney crystal deposition. They are generally considered more dangerous than insoluble oxalate plants because the toxic compounds enter the bloodstream rather than staying in the GI tract.
Star fruit (carambola) is particularly relevant for households where fruit is left on counters. The Merck Veterinary Manual groups sour star fruit with rhubarb as a soluble oxalate plant, so large amounts can cause problems through the same calcium-binding mechanism.
The shamrock plant (Oxalis species) is a common houseplant that contains soluble calcium oxalates, and the ASPCA lists shamrock as toxic to dogs, though it notes kidney failure is rare in dogs and cats. It looks harmless and is often given as a gift around St. Patrick’s Day. Worth knowing if you have dogs that chew houseplants.
Insoluble Oxalate Plants: More Common, Less Systemic
Insoluble calcium oxalate plants are common houseplants. Dieffenbachia and Philodendron belong to the Araceae family, which also includes pothos, peace lily, Chinese evergreen, caladium, and calla lily, making this group one of the most widespread houseplant hazards.
Key distinction: insoluble oxalate plants do not pose a kidney injury risk the way rhubarb does (Merck Veterinary Manual). The concern with Dieffenbachia and Philodendron is oral pain, throat swelling, and in rare severe cases, airway obstruction.
For owners of breeds like the Golden Retriever, Labrador Retriever, or Beagle that are known to eat things they should not, both categories of oxalate plant deserve attention in the home and garden.
Practical Garden and Home Safety
Removing rhubarb entirely is the cleanest solution if you have a dog with garden access.
If removal is not practical, physical barriers work. Dog-proof fencing around the rhubarb patch is the most direct prevention strategy. Raised garden beds deter some casual browsing, though determined diggers or jumpers will still need solid barriers.
Indoor checklist for oxalate plant safety:
- Move Dieffenbachia, Philodendron, and Pothos to rooms the dog cannot access
- Do not leave star fruit on low counters or accessible fruit bowls
- Check any new houseplant against the ASPCA toxic plant database before bringing it home
- Discard cut rhubarb leaves directly into sealed bins, not open compost
The ASPCA toxic and non-toxic plant list covers hundreds of plants, with notes on which are toxic to dogs, cats, and horses. Cross-referencing before a new plant enters the house takes under a minute and covers risks well beyond oxalates alone.
For breeds that are already predisposed to chewing and exploring, like the Australian Shepherd, Border Collie, or Jack Russell Terrier, garden supervision alongside physical barriers is the most realistic prevention approach. Training alone is not enough when a dog is bored, unsupervised, or has already discovered the plant smells interesting.
Providing safe dog chews as a redirect gives high-chew dogs an alternative outlet, reducing the chance they turn to garden plants for oral stimulation. It is a small thing, but it closes one of the more common paths to accidental plant ingestion.
FAQ on Rhubarb And Dogs
Is rhubarb toxic to dogs?
Yes. Rhubarb is toxic to dogs and is listed as such by the ASPCA Animal Poison Control Center. The leaves contain soluble oxalates that can cause drooling, vomiting, low blood calcium, tremors, and kidney damage in dogs of all breeds and sizes.
Which part of the rhubarb plant is most dangerous?
The leaves. They carry the high soluble oxalate levels responsible for poisoning. Veterinary toxicology sources consider the stalks low risk, but no part of the plant is a recommended food for dogs, and leaf ingestion carries the real risk of kidney injury.
What happens if a dog eats rhubarb?
After a large leaf ingestion, oxalic acid binds with calcium in the bloodstream, forming calcium oxalate crystals that can deposit in the kidney tubules. This causes hypocalcemia and kidney injury. Symptoms include drooling, vomiting, tremors, and reduced urination as kidney function drops. A small nibble usually causes only mild stomach upset.
How quickly do symptoms appear?
Drooling and mouth irritation can start within minutes of chewing, and vomiting or lethargy usually follows within a few hours. Kidney-related signs can take a day or more to develop, which is why vets recommend treatment before symptoms appear.
How much rhubarb is dangerous for a dog?
There is no established safe dose. Any leaf ingestion warrants contacting a vet. Small breeds reach harmful oxalate levels with less plant material, so even part of a large rhubarb leaf may be enough to cause problems in a dog under 10 kg.
What should I do if my dog eats rhubarb?
Call the ASPCA Animal Poison Control Center at (888) 426-4435 or your vet immediately. Do not wait for symptoms. Do not induce vomiting without direct veterinary instruction. Note the time of ingestion, which plant part was consumed, and the estimated quantity before calling.
Can dogs eat cooked rhubarb?
It is not recommended. Cooking reduces oxalate content but does not make rhubarb leaves safe. Cooked stalks are low risk for oxalate poisoning, but rhubarb pies and jams are high in sugar, which typically causes gastrointestinal upset, and the stalks offer dogs no nutritional benefit.
How do vets treat rhubarb poisoning in dogs?
Treatment involves induced emesis if ingestion was recent, followed by activated charcoal to limit further absorption. IV fluid therapy for 24 to 48 hours supports the kidneys and corrects dehydration. Calcium gluconate is given intravenously if blood calcium is low. Many dogs need hospitalization for BUN and creatinine monitoring.
Can a dog fully recover from rhubarb poisoning?
Yes, when treated quickly. Dogs treated early before significant kidney involvement have good recovery rates. A 2022 study in the Journal of Veterinary Internal Medicine found serum creatinine normalized in 75% of dogs recovering from acute kidney injury from all causes.
Are other common plants also toxic to dogs through oxalates?
Yes. Star fruit (carambola) and shamrock (Oxalis species) contain soluble oxalates with the same kidney-damaging mechanism as rhubarb. Dieffenbachia and Philodendron contain insoluble calcium oxalate crystals, causing oral pain and swelling but not the kidney risk of rhubarb.
Conclusion
Rhubarb and dogs are a genuinely dangerous combination that most pet owners underestimate until it is too late, and the leaves are where the danger lives.
The core risk comes down to soluble oxalate toxicity. Oxalic acid binds systemic calcium, deposits crystals in the renal tubules, and can drive acute kidney injury faster than symptoms suggest.
Small breeds, dogs with pre-existing kidney disease, and those with repeated exposure carry the highest risk.
Treatment works when it starts early. Decontamination, IV fluid therapy, and calcium gluconate when needed give dogs a strong recovery trajectory if you act before significant kidney damage sets in.
Call the ASPCA Animal Poison Control Center at (888) 426-4435 the moment your dog eats rhubarb leaves. Do not wait for clinical signs.
