Tartaric acid and its salt potassium bitartrate are the proposed toxic principles in grape and raisin toxicosis in dogs, but no reliable minimum toxic dose exists due to variable tartaric acid content across grape varieties. Tartaric acid is transported into canine proximal tubular cells via organic anion transporter-1 (OAT-1); dogs lack the OAT-4 transporter present in humans that would otherwise secrete tartaric acid into tubular fluid for urinary excretion, causing accumulation in proximal tubular cells and species-specific nephrotoxicity.Journal of Vete… Tartaric acid content in grapes ranges from 0.35% to 2% depending on variety, growing conditions, and ripening stage, meaning the same gram-per-kilogram dose of grapes delivers a highly variable tartaric acid load.Journal of the… This variability explains why some dogs develop acute kidney injury (AKI) after ingesting four to five grapes while others remain asymptomatic after ingesting up to 1 kg of raisins.Journal of Smal…
The lowest reported doses associated with AKI are 19.6 g/kg body weight for grapes and 2.8 g/kg for raisins, but these are observational minimums, not established thresholds. Assuming a tartaric acid content of 1%, grape doses of 20–150 g/kg correspond to tartaric acid doses of 196–1,484 mg/kg.Journal of the… One source calculates that 5 g of cream of tartar is approximately equivalent to the tartaric acid in 120 g of raisins, yielding a tartaric acid dose of 0.5 g/kg for a 10-kg dog ingesting 12 g/kg of raisins.Journal of the… Because no dose-response relationship has been established, any grape or raisin ingestion in a dog should be treated as a potentially toxic exposure regardless of quantity.Journal of Smal…
Decontamination is the immediate priority. Current standard management includes prompt emesis induction, intravenous (IV) fluid therapy, and supportive care; no specific antidote is currently available.Journal of the…+1 In the cases where decontamination was not performed and treatment was delayed, 4 of 6 dogs were euthanized, 2 became anuric, and 1 became oliguric.Journal of Vete… Dialysis is indicated in severe cases.Journal of the…
The overall prevalence of AKI in dogs presenting with known grape or raisin ingestion is 6.7% (with 88% of those dogs having undergone gastrointestinal decontamination), and mortality is low in treated patients. Of 139 dogs presenting after ingestion, 138 survived and 1 died; 2 dogs required continuous renal replacement therapy.Journal of Vete… Dogs presenting later had a numerically higher AKI prevalence (9%) compared to early presenters (4.5%), though this difference was not statistically significant.Journal of Vete…
Neurological signs occur in addition to AKI and are a negative prognostic indicator. Vomiting occurs within 24 hours in 81% of dogs and within 48 hours in 100% of dogs.Journal of Vete… Oliguria or anuria develops in 49% of affected dogs, and azotemia develops within 2 days of ingestion.Journal of Vete… Neurological signs localizing to the forebrain and cerebellum are present in more than 75% of severely affected dogs; ataxia has a median onset of 2 days (range 0.6–6 days) after ingestion and is associated with a negative outcome.Journal of Vete…
Two investigational strategies targeting the tartaric acid mechanism are under evaluation but are not yet clinically validated. Probenecid, an OAT-1 inhibitor, blocks uptake of tartaric acid into Madin-Darby canine kidney cells in vitro and has been shown to be bioavailable and safe at 50 mg/kg PO as a single dose in healthy dogs, but clinical trials in dogs with actual tartaric acid ingestion have not yet been completed.Journal of Vete… Oral calcium carbonate has been proposed as an adjunctive treatment based on its ability to form insoluble calcium tartrate in the gastrointestinal tract (analogous to its use in oxalate and fluoride poisoning), theoretically reducing systemic absorption, but this approach has not been clinically validated.Journal of the…
Tamarind ingestion carries the same risk and should be managed identically to grape or raisin ingestion. Clinical signs, laboratory findings, and histopathologic lesions following tamarind ingestion are similar to those of grape and raisin toxicosis, consistent with tartaric acid as the shared toxic principle.Journal of Vete… Processed grape products such as juice, jam, and wine are lower risk because excess tartrates are removed during commercial processing.Journal of the… True currants of the genus Ribes have not been associated with renal injury; only Vitis genus fruits (grapes, raisins, Zante currants) and tamarinds carry this risk.MSD Vet Manuals
| Exposure | Lowest Reported Toxic Dose | Estimated Tartaric Acid Dose (at 1% content) | Key Caveat |
|---|---|---|---|
| Grapes | 19.6 g/kgJournal of Vete… | 196 mg/kgJournal of the… | No dose-response relationship; any amount warrants treatmentJournal of Smal… |
| Raisins | 2.8 g/kgJournal of Vete…+1 | ~500 mg/kg (via cream of tartar equivalence)Journal of the… | Variable tartaric acid content across varietiesJournal of the… |
| Cream of tartar | 5 g ≈ 120 g raisins for 10-kg dogJournal of the… | 0.5 g/kg for 10-kg dogJournal of the… | Direct tartaric acid source; decontaminate immediatelyJournal of Vete… |
| Tamarind | Not quantified | Not quantified | Same clinical syndrome as grapes; 4/6 reported dogs euthanizedJournal of Vete… |
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